generation would have perfect spires, the decollation not being transmitted.

White varieties would seem to be caused by the non-development of the colour-forming organ, but, again, as in the cases given above, white varieties are also local, being confined to one spot, or to one neighbourhood, and it is rarely that, one having been found, a careful search does not reveal others. That these white or colourless varieties are due to the nature of the food or of the soil is unlikely, because they are always, or nearly always, found with typical coloured specimens.

It cannot be due to a contagious disease of the colour-gland, as in that case we should find specimens which had commenced life with coloured shells, but having subsequently lost the colour-forming function, would have the last few whorls colourless; and I

and why do they vary so much? All I can say is that I do not know why, but it would seem that form from which the now existing helices were developed had five definite bands, like H. nemoralis ; or perhaps, we may go still farther back and say that the form from which all the Gasteropoda sprung, the first type of the Gasteropod shell-bearing Mollusc, was banded. The reason for this speculation is that the bands are always in the same relative position in the Gasteropoda when they are developed, the band just above the periphery being specially characteristic. However, this is a subject to which little attention seems to have been given, but I think that it will well repay research.

In the present paper I shall not deal with so huge a subject as the variation of the mollusca throughout the world; I leave this to others, and shall only describe the variation of the mollusca in the counties of Kent, Surrey, and Middlesex, the counties which I am now working.

have never seen or heard of such a specimen. Again, there are the colour varieties, also local in their distribution, and apparently, though of course not really, without cause. The bright colours of some varieties of Helices, such as H. nemoralis, seem even to be injurious, as they make the shells such conspicuous objects as they crawl, and enable the birds to find them readily; and that birds do eat numbers of these brilliantly coloured snails, is well testified by the heaps of broken shells round a suitable breaking-stone. But there is one instance, that of the green H. nemoralis at Crayford (see page 236), in which variation would appear to be protective, but it was a variation in the animal, and not in the shell, that caused the green tint.

And there are many other points which seem to me to need careful study before any conclusions can be arrived at, and I will give an instance: of what use are the bands to the helices? why are they developed?

GASTEROPODA.

Neritina fluviatilis.-This shell does not seem to vary much, and I have never taken an abnormal form. Nevertheless four varieties have been recorded as British.*

Paludina vivipara.-The bandless form (var. efasciata, var. unicolor), has been recorded from Richmond, I have not taken it myself.

Bythinia tentaculata. -The colourless or white variety occurs in the district, and the varieties ventricosa and excavata are also recorded. Monst. decollatum I have found at Barnes.

B. Leachii.-Var. elongata is recorded for West Kent. Valvata piscinalis.—I have taken a variety showing traces of bands; var. subcylindrica, a dead shell at Hammersmith. The type and a variety approaching var. depressa occur fossil at Crayford.

Planorbis lineatus, var. albina has been recorded for East Kent.

Planorbis nautileus.-This has two main forms, the so-called type and the var. crista. Both are found in the district.

Planorbis spirorbis.-A dead shell of var. albida at Bedford Park (D. B. Cockerell).

P. vortex.-At Fulham I have taken a variety of this species. (See p. 14.)

P. carinatus.—I have found the variety disciformis near Guildford.

P. complanatus.-Mr. J. W. Taylor describes the monst. sinistrorsum from a specimen found by Miss Hele at Wye. This instance of a sinistral monstrosity of Planorbis is, I believe, unique. The white variety is said to have been taken in West Kent, and also the var. rhombea.

P. corneus. This species varies in size, the largest specimen I have found is from Ealing. The young

Mr. R. A. Freeman has a specimen having a broad white band below the periphery which he found near Barnes.

shells are sometimes striated like P. albus. Some specimens collected at Minster have a reddish tinge. I have taken the white variety in Thanet, and also a single young specimen at Kew Gardens. The white var. has also been reported as occurring in Middlesex. Physa hypnorum.-The mouth of this shell is sometimes tinged with pink.

Physa acuta.-This is not really a British shell, the only locality for it being one of the water-lily tanks in Kew Gardens, where it is abundant. One of my specimens has the bands 4 and 5 slightly developed.

Physa fontinalis.-This varies in size; my largest specimen I took at Ealing, with the large P. corneus, it is slightly more than of an inch in length. I have taken a single specimen of the white variety at Herne Bay, living with the type.

I

T. D. A. COCKERELL.

(To be continued.)

AN AQUARIUM IN A BOTTLE.

HAVE kept small shore crabs (Carcinus mœnas) in wide-mouthed glass pickle bottles for many months, and also hermit crabs (Pagurus Bernhardi), but the former do the best. Serpulæ (Serpula triquetra), and also very small terebella do well too, but I have never been able to keep full-grown mussels for more than a day or two. My plan is to fill the bottle one-third full of fine sand, and place on this a large stone with a piece or two of ulva growing on it. This stone is tilted up in such a way, that there is deep water (comparatively speaking), in the front of the bottle, while behind it is only just covered. When first made a strip of paper should be pasted on behind to mark the level of the water, and it should always be kept up to that level with a spoonful or so of fresh water, as needed, to make up for the loss by evaporation. The less water there is in the bottle, the better; it will be found quite sufficient to fill it half or two-thirds full (including the sand). The plan suggested by Mr. Lovett (vol. xx. p. 75) will be found a very good one by those who have not a cool place in which to stand the bottle in hot weather. If the water turns a little green, placing it in the shade a day or two, I find soon remedies it. If anything goes wrong, and the water turns black, I pour it into a clear glass bottle, put a few pieces of confervæ in, and place it in the sunshine; the oxygen produced by the influence of the sunlight on the seaweed soon neutralizes the offensive gases produced by putrefaction, and in a short time the water is as clear as ever. I do not shake the water, but let it remain constantly still; shaking it retards the purifying process. Although I use bottles when I have so many creatures, such as crabs, requiring isolation that I scarcely know what to do with them, I do not recommend the plan, except as subsidiary to

other aquaria. A propagating glass can be bought for a few pence, and this inverted and placed on a suitable stand will be found by far the best. Stocked with anemones, serpulæ, terebellæ, a young nereis, periwinkles, very small mussels, and a few acorn barnacles with, perhaps, one or two small prawns, it will be a constant fund of amusement and instruction. A few pieces of green seaweed will make it look very effective, but care must be taken not to introduce too much, or it will decay, and blacken the water. Fish and crabs require vases to themselves, as they will neither agree with the other inmates nor among themselves.

Cambridge.

ALBERT WATERS, B.A.

A NET FOR MICROSCOPISTS.

S the bright days increase in number, every one is led involuntarily to look over his collecting apparatus in anticipation of that sudden starting into renewed life of all aquatic vegetation, and the consequent crowds of Infusoria, Entomostraca, &c., which afford all those who are keenly interested in their birth and "education," such an endless amount of pleasant recreation. The pleasure of such collecting, I always think, is greatly increased by the use of a convenient net, which should enable one to remove any object of value, and recommence the netting without unnecessary loss of time.

The methods usually adopted for attaining this, are, either to wash the muslin in a wide-mouthed jar, which must therefore be carried out on all expeditions, or to use a set of muslins, each one of which when sufficiently covered with life, is removed and dropped into a bottle, of necessity, large and cumber

some.

I tried the simpler of these two modes, i.e. washing, for some time, but never found that the result was altogether satisfactory, many specimens of worth being washed out of the net, if its passage through the water happened to be in the least degree hurried.

A B

The next that I tried was a deep conical net, stretched upon a framework of cane, bent (after boiling) somewhat to the shape of an iron hook, Across the semicircular portion, i.c. from A to B, I stretched a copper wire, not less than six inches in length, which served as a finer cutwater than the cane, and made a strong and effectual "scraper " for such stems as those of the water lily. I had, from the first, considerable difficulty in turning a net of this shape inside out, and, to overcome this, at length contrived one, whose construction I hope the following explanations will render sufficiently clear to enable those who may care to copy it to possess one similar to my own. The framework is precisely the same as that shown above. The muslin bag is so arranged that the point of the cone comes exactly opposite to

the centre of its mouth when stretched out behind it, and within this point is inserted a half-inch test-tube having the bottom ground off. The ends of the muslin for the space of half an inch are bound tightly round the head of the tube; the projecting rim of the glass preventing it from being pulled out. Round the whipping is placed a broad band of cork-a wine cork with the centre burnt out, and the edges bevelled forward, to prevent undue resistance to the water, which keeps the tube always behind the muslin, and ready to receive the contents of the net; otherwise, when the net is moving very slowly in the water, the tendency of the tube is to sink below the mouth, thereby causing all animal life to be merely washed in and out again. The tube is closed by placing a square of muslin over the open end, and securing it with a very small band of india-rubber. It is worth remembering that duplicates of both muslin square and elastic band are indispensable, these being the two most important parts of all.

Care should be taken when cutting the muslin that the piece coming from the wire be quite flat and remain so after being fixed in its place, for if there is any looseness near the wire, thereby forming a small hollow below the level of the tube head, solid matter, instead of flowing at once into the tube, will "hang" in this hollow. When it is required to remove the contents of the net to the collecting bottle, proceed thus.

After a favourable spot has been thoroughly fished, the net should be drawn in to the bank, raised from the water as rapidly as possible, and the thumb of the right hand pressed tightly against the bottom of the tube, so that it may be kept full of water. All that is within may then be readily examined, by holding the glass against the light, when organisms of any size are at once discerned, and the small diameter of the tube does not prevent the use of a pocket lens, which is practically useless when the objects are procured in the dipping bottle. If the tube contains anything of value, the thumb of the left hand should be placed upon the head of the glass, which should then be turned upside down, the square and band removed, and the water gently poured into a medicine bottle, this being a shape of vessel admirably adapted for carriage in a pocket. In constructing this net, it is advisable so to arrange the muslin, that when travelling in the water the wire may precede the cane, for, when skimming, if the shadow of the framework is allowed to pass over the life collected on the surface before the wire with the net attached is able to follow it up, it is more than likely that many specimens will make good their escape. After using this net for a few minutes, I have always found more in the glass tube than others have been able to collect in as many hours, while using the favourite bottle and stick; and it is worth remembering that each plunge of the dipping bottle adds seldom less than half-a-pint of water to the total amount that must be carried, perhaps for

miles, while the net and tube increases the amount by never more than one table-spoonful. Indeed, I have frequently returned from half-an-hour's collecting with enough in my medicine bottle to occupy me for many evenings, and to completely colonise a two gallon globe. I generally cut a stick from the nearest thicket, to lengthen the handle, which gives one a wider field for netting, the size of which, naturally, is in proportion to the length of stick obtained. The whole construction of this net is so simple that from the boiling of the cane to the first trial in the waterbutt, occupied me for little more than an hour, and, to adopt the language of advertisements, "since that time I have used no other."

Should these explanations not be sufficiently clear to enable those who are desirous of copying my design to do so to their own satisfaction, I shall be very pleased to forward more exact dimensions, and a paper pattern of my own net to any who may apply for it. HERBERT ALEXANDER Walters.

The Hermitage, Reigate.

STUDIES OF COMMON PLANTS.

[Continued from p. 62.]

No. II. THE CUCKOO-PINT (Arum maculatum) (continued).

By CHARLES F. W. T. WILLIAMS, B.A. Cantab.

THE

HE next disease to be noted is one which frequently causes mistake and annoyance to the ardent searcher after micro-fungi. I mean a decomposition of internal cell structure, extending over but a small area, and clearly apparent to the naked eye in the form of dirty brown or light spots. Again and again beginners, and others, who I presume lay claim to being something more, send me leaves of the arum thus marked, in the fond belief that they have found the somewhat uncommon Ecidium ari, in large quantities! Only the other day, I heard of the case of a gentleman who devoted much time and trouble to the examination of such leaves, but in the end confessed to the lady who had brought him the valuable specimens that "he could see nothing." It may be well then to bear in mind that there are two forms of disease which should be distinctly separated from one another in the mind and the eye of the enthusiastic collector. And this brings me to speak of the actual attack of the fungus known as Ecidium ari.

In the first place, as I have mentioned, Ecidium ari is not common. The leaves on which it appears are not always marked on the upper side, and, as is so often the case, are more frequently healthy in appearance than the reverse. In general, however, there is some slight indication on the upper surface of the

lamina of mischief below. On turning the leaf over, round orange-coloured spots will be observed scattered over the leaf, and in some cases affecting the petiole. The central peridia are abortive. Most of these points can easily be distinguished with the naked eye.

Dr. Cooke's description is as follows: Ecidium ari, Berk.; wake-robin cluster cups; spots round, confluent; peridia circinative, not crowded, central ones abortive.

The whole plant seems to exist very comfortably even when severely affected with this fungus. Many of the unhealthy plants of arum I have examined this season have been entirely free from the Ecidium, though in company with numbers affected. plants in this part of the country are only locally affected, one locality only furnishing specimens.

The

It is now time, I think, to pass on to the contemplation of that interesting and curious structure, the spadix. The spadix of the arum, commonly known as "the flower," is well calculated to puzzle the novice at botanical description. The spadix is enclosed in a green spathe, considerably longer than the spadix. This spathe, on opening, is sometimes found to be spotted in the same manner as the leaves, only the colour is brighter, and the spots have the appearance of being raised above the surrounding tissue. It does not follow that the plants whose leaves are spotted have their spathes spotted also. The spadix terminates in a naked cylindric column contracted below the middle. The colour of the column is dull purple, or sometimes yellow; rarely white. The shades of purple vary somewhat, but it is not common to find the yellow and white varieties, though I have done so several times this season.

The column has a very velvety appearance and is beautifully smooth to the touch. On examination it will be found to be covered externally with minute papillæ, secreting colouring matter (Fig. 61). These are very minute, and the best way to view them is to take a very thin section of the column and view with aor. The column is of cellular structure with every cell so closely packed with starch grains that, as in the corm, it is very difficult to discern the tissue of which it is composed, except in the centre through which run cells with numerous air cavities; raphides can also be seen. I have noticed this year a curious disease of the column which may possibly be common enough, only it has never before come under my notice. In numbers of cases on the spathe opening, I have discovered the terminative column of the spadix covered with a mould. In some instances the column presented a miserable shrivelled appearance, while in other cases perfect size was gained. In very few cases did the diseased column affect the organs of reproduction. Many of the plants noted by me as so affected are now in fruit. The column showed very plain signs of disease throughout its structure. If picked and brought home the spadix so diseased

gradually reached a gelatinous consistency, and emitted a most offensive odour. It would be interesting to have the work of some authority, on the subject of this mould. Unfortunately, the time is so short between the opening of the spathe and the fall of the column that almost hourly attention would have to be given to the matter.

Leaving the column and descending the spadix, we come first of all to a ring of organs which in reality are aborted stamens or staminodes; next to these are a crowd of sessile anthers. The pollen possesses no special feature in markings or shape. Below the anthers are a ring of rudimentary ovaries, and lastly a crowd of naked sessile ovaries. Fig. 62 shows the

spadix with the spathe removed, with the various organs I have mentioned. The fruit of A. maculatum is a berry, a large quantity being clustered together, bursting the base of the spathe, which is persistent. When ripe the berry becomes red, and should be most carefully avoided by all persons having a tendency to taste luscious-looking berries, or the result of the repast may be alarming, if not serious. Should a child be unfortunate enough to eat any of these berries, an emetic should be given, and the mouth should be carefully cleansed from all particles of berries remaining there.

There is one curious property connected with this plant, which it would be very negligent not to mention. I mean the power of evolving heat possessed by the spadix on its first opening. I had hoped to give a

table of my own experiments on this subject; but though I tried time after time to take a reading, I regret to say I failed. Either I was on the spot too early or too late, and I have really nothing, for this season, at any rate, of a reliable nature to record on my own account. I must content myself, therefore, by giving a quotation on the subject from the late Professor Balfour's Class Book of Botany, p. 522. After remarking on the evolution of heat during flowering, and the fact that the natural order Aroideæ present the most marked instances of this evolution, the Professor says, "Deubrocket's examination of the spadix of Arum maculatum gives the following results:

From these observations, it appears that the maximum of temperature in the spadix occurred at 5.30 P.M., one hour and a half after the complete opening of the spathe, and that the heat was 18.7° above that of the surrounding air." The spadix emits a curious odour, resembling that of the thyrse of the horse chestnut.

As with the corm so with the fruit, starch and raphides are found in every section examined. Professor Gulliver, in his paper on "Plant Crystals," (SCIENCE-GOSSIP, p. 97, 1873) mentions the occurrence of raphides in the berry of A. maculatum, and on page 98 gives a figure of the same. The raphides of the berry appear to be larger than those of other parts of the plant. Many months will have to pass before again an opportunity is given of observing in all its various details this interesting plant; but when that time arrives, there will yet be found much material for examination, and a field for interesting research, and perchance new discoveries.

Bath.

MR. G. C. WALKER, F.R.C.S., writing to the "Lancet," says that after he had operated for cataract upon a favourite fox-terrier belonging to a friend, chloroform having been used, the animal appeared after the operation to be completely dead, none of the remedies tried producing any good effect. At length it occurred to him to employ artificial respiration and nitrite of amyl simultaneously, instead of separately as he had already done. The result was that "two or three compulsory breathings of the amyl caused the dog to jump up and stagger about the room most actively." Since that time Mr. Walker makes it a rule not to administer chloroform without having nitrite of amyl at hand.

“γου

MY GARDEN PETS.

By E. H. ROBERTSON.

PART I.

YOU are so fond of dumb creatures, have you no other pets?" was one day the enquiry of a friend, who, from my dining-room window, had been long admiring my trustful window pets.

"Many," I replied; "follow me, and you shall see them."

I led him, all expectation, into my garden, where, at a few paces from the house, stood a row of beehives, and smilingly was about to remark that there were a few thousands, but was arrested by his disappointed exclamation, "Oh, bees!" "This does not augur well for his interest in my pets," thought I, and the added assertion, "But you can't make pets of them—they can't be tamed-such little things can't possibly know you," drew from me the reply, "Indeed! I not only can, but do, make pets of them, and they certainly know me as well as, perhaps better than, the birds do."

Although politeness kept him silent, the look of incredulity with which he regarded me told me plainly what he thought.

"Are you afraid of bees?" I asked. His stammered out "N-no. Oh, n-no," as, after turning up the collar of his coat, and down the brim of his felt hat, he plunged his hands into the depths of his trousers pockets, and fell into the rear, led me, however, to think that it would be wise to protect him from possible attack.

The alacrity with which he retreated into the house when I suggested that he should be veiled and gloved did just a little amuse me, I must confess, and when I add that, although my dear friend is the author of works treating largely upon bees and ants, he yet does not really know the difference between the largest Bombus and an ordinary honey bee, I think my readers, also, will give free scope to their sense of the ludicrous. Be-veiled, be-gloved, and closely buttoned up, my bee-literary friend was again brought forth, to be led to a spot where stood my four strongest stocks. It was a lovely summer day, and, honey being abundant, my pets were, in their thousands, pouring in and out.

"Aren't you afraid of their stinging you?" asked my friend tremblingly, as, standing a little on one side of a hive, so as to allow homing bees to enter, I placed my bare hand upon the alighting board. I made no reply, and as the in and out-flowing streams passed over my hand and I yet remained unhurt, he saw that his question was unnecessary. Presently, "Dear me, how very singular-most remarkable. Evidently look upon you as a personal friend."

"Well, so I am."