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places but as prisons. This, however, seems highly , found. This may not, however, have been the case improbable, as the structures evidently were in with all double-holed bullâns, as in some cases the tended as tombs, and as the dish-shaped bullâns holes are of nearly equal depths and of different seem to be a necessary appendage to the large carns, shapes. Near Killgoola, west of the lower portion it appears probable they were connected in some of Lough Corrib, are a pair of small bullâns cut in way with the ancient funeral rites. The small, the solid rock, of nearly equal size, and called Gluine shallow bullâns, as far as we are aware, are always Phaudrick (Anglicè, Patrick's Knees), as the saint found in or close to churches, and were evidently is said to have worn them praying. Their original used either as baptismal fonts, or for holding water use seems very obscure. The word bullân properly for washing purposes. Some are nearly rectangular means any conical substance, or a circular excata. in shape, while between the small dish-shaped bullân tion ; thus water-worn holes in rocks are called to the stalked or pedestal font of the present day, bullâns, also a cow's teats; both from their shape there are regular gradations.

and aperture. In olden times baptismal fonts, from

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Many, if not nearly all, the bowl-shaped bullâns may have been used as baptismal fonts, but some were undoubtedly used as corn-crushers. This has been proved by Dr. W. King, of Galway. At Roscapne Round tower, near Galway, are two stones, one containing three bullâns and the other two; and

being circular excavations in stones, may have been so called, but they are called in modern Irish Umarbaisdidh, or baptismal troughs. To us it would seem probable that the bullâns at the churches may have been put to more than one use, sometimes being used as fonts, at other times as corn-crushers, or even for grinding up the herbs, &c., used for the distillation of the drinks of the period. The latter suggestion would specially refer to the five-holed bullân, called Leac-na-poul, or the holed flag, at Cong (fig. 157), as it was in the vicinity of a large abbey, a place where probably there was a large consumption. Those also in such localities as the mountains near Adrigole, Tulla, &c., may have been used for bruising the heather for the manufacture of the ale about which we hear. Un. fortunately the process is now unknown ; but that the heather was once valuable seems probable, ag otherwise we would not find the remains of the walls and fences dividing up the wild heathery mountains into small lots.

From bullâns we naturally go to the holy wells, as many of the former are thus designated. These wells are dedicated to different saints, although probably they were a pagan custom that was engrafted on to the Christian religion. At various times the priests of the different forms of Christianity bave tried to do away with them, but without success, and at the present day they are much venerated and visited. Without doubt they are efficient in some diseases, such as sore eyes ; this, however, is just as probably due to the regular

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the editors of the Journal of Horticulture at the beginning of June, and my reply to the correspondeut was printed on June 10th. The leaves were badly diseased, and I detected the Peronospora in very small quantities here and there, emerging from the breathing pores. This was a week or ten days before Mr. Berkeley brought the matter before the Scientific Committee of thc Royal Horticultural Society; and when I heard Mr. Berkeley's remarks about the Protomyces, I immediately accused myself of great carelessness in possibly overlooking it; but I was equally certain of the presence of the Peronospora in the specimens I examined.

On receiving authentic specimens of diseased plants from Mr. Barron, of Chiswick, the brown spots on the potato leaves at once reminded me of the figures of some species of Protomyces, and the dimensions agreed tolerably well with some described plants of that genus; but the spots, when seen under a high power, appeared very unlike any fungus, and they were very sparingly mixed with other bodies much smaller in diameter, and with a greater external resemblance to true fungus spores. These latter spore-like bodies were of two sizes -one transparent and of exactly the same size as the cells of the leaf (and therefore very casily overlooked), and the other darker, possibly reticulated, and smaller. A few mycelial threads might be seen winding amongst the cellular tissue, and these threads led me to the conclusion that the thickened and discoloured spots on the leaves were caused by the corrosive action of the mycelium, in the same way as peach, almond, walnut, and other leaves are thickened, blistered, and discoloured by the spawn of the Ascomyces, as illustrated at the last meeting of the Royal Horticultural Society.

My opinion, therefore, was soon formed that the “new” potato disease (as it has been called) was no other than the old enemy in disguise, or, in other words, that it was the old Peronospora infestans in an unusual and excited condition. That climatic conditions had thrown the growth of this fungus forward and out of season was probable; but the idea that the pest would not at length attack all and every sort of potato was to me most unreasonable, though the more tender sorts might be the first to suffer.

Suspecting the two-sized small bodies before mentioned to be of the nature of spores, and remembering my experiments during last autumn with ketchup, in which I observed that the spores of the common mushroom might be boiled several times, and for lengthened periods, without their collapsing or bursting, I thought I would try to set free the presumed spores in the potato leaves by macerating the foliage, stems, and tubers in cold water. This maceration was necessary because the tissue of the diseased leaves was so opaque and corroded, and the cell-walls were so thickened, that it was difficult to

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distinguish the threads and suspected spores from my observations lead me to think that conjugation the cellular tissue. I did not treat the leaves with frequently takes place after both organs are quite boiling water because I wished to keep the threads free. The antheridia and oogonia are best seen and spores alive.

in the wettest and most thoroughly decomposed From day to day I kept the diseased leaves, stems, | portions of the tissue of the decomposing tuber, but and tubers wet between pieces of very wet calico, in they occur also in both the stem and leaf. I conplates under glass, and I immediately noticed that sider Mr. Alexander Dean's remark, as reported in the continued moisture greatly excited the growth the Gardeners' Chronicle for June 19th last, p. 795, of the mycelial threads; this to me was quite unex- to have a distinct bearing on this point, where he pected, as I had merely wished to set the spore-like says, “In all cases where the seed tubers were cut bodies free. So rapid was now the growth of this they were quite rotten.” mycelium, that after a week had elapsed, some Before I referred to De Bary's measurements decayed parts of the lamina of the leaf were tra of similar organs in other species of Peronospora, I versed in every direction by the spawn. Thinking was disappointed with the results of my observa. the close observation of this mycelium in the now tions, and felt disposed to refer the bodies and thoroughly rotten and decomposed leaves might

threads in the potato leaves to Saprolegnia; but end in some addition to our knowledge of Perono a glance at the figures now published and the spora infestans, to which fungus I had no doubt similar figures copied from De Bary to the same from the beginning that the threads belonged, I scale, will show that if the bodies observed by me kept it under close observation, and in about ten are Saprolegria-like, the oogonia and antheridia days the mycelium produced a tolerably abundant figured by De Bary show an exactly similar alliance. crop, especially in the diseased tubers of the two. Still, as the Saprolegnieæ are at present defined, sized bodies I had previously seen and measured

I am by no means inclined to describe the bodies in the fresh leaves. The reason why these objects, observed by me as really belonging to that tribe of which undoubtedly occur in and about the spots, plants. are so extremely few in number in those positions

The Saprolegnieæ have the habit of moulds and is, I imagine, because they require a different set of

the fructification of algæ, and they live on organic conditions for their normal growth, and these

matter, animal and vegetable, in a state of putreconditions are found in abundant and continued faction in water. One of the best known of these moisture.

plants is Botrytis Bassiana, the parasite which The larger of these bodies I am disposed to con

causes the disease of silkworms. Now the genus sider the “oogonium” of the potato fungus, and

Botrytis among fungi is almost or quite the same the smaller bodies I look upon as the “antleridia” with Peronospora, to which the potato disease beof the same fungus, which are often terminal in longs; and I consider it a strong argument in position. The filaments of the latter are commonly

favour of my Saprolegnia-like bodies being the septate, and sometimes more or less moniliform or

oogonia and antheridia of the Peronospora when necklace-like. Both oogonium and antheridium are such an authority as Mr. Berkeley considers one of very similar in nature and size to those described as

the Saprolegnieæ (Achlya) "may be an aquatic form belonging to Peronospora alsinearum and P. umbel. of Botrytis Bassiana--the silkworm disease. liferarum ; and this is another reason (beyond my The common fungus which attacks flies (so fre. seeing undoubted P. infestans on potato leaves at

quently seen on our window.panes in autumn), the beginning of June) why I am disposed to look Sporendonema muscæ, Fr., is said to be a terrestrial upon these bodies as the oogonium and antheridium condition of Saprolegnia ferax, Kutz., which latter of the potato fungus.

only grows in water; and if a fly infected with the The larger bodies are at first transparent, thin, fungus be submerged, the growth of the Saprolegnia pale brown, furnished with a thick, dark, outer wall,

is the result. 3 It would now seem to be somewhat and filled with granules; at length a number (usu

the same with the potato when diseased, in the ally three) of vacuities or nuclei appear. The fact that when submerged a second form of fruit is smaller bodies are darker in colour, and the external produced. coat is apparently marked with a few reticulations, Between the two moulds, Botrytis and Peronopossibly owing to the collapse of the outer wall. I spora, there is little or no difference; the characters have observed the two bodies in contact in several

of Corda, founded upon the continuous or septate instances. After fertilization has taken place, the filaments, cannot be relied upon, and even De Bary outer coat' of the cospore enlarges, and soon gets

himself figures P. infestans with septate filaments, accidentally washed off in water. Both antheridium like a true Botrytis. The intimate connection, howand oogonium are so slightly articulated to the ever, between the Saprolegnieæ and some moulds threads on which they are borne that they are cannot be denied, as the instances above cited detached by the slightest touch, but with a little care clearly show; and I am therefore disposed to think it is not really difficult to see both bodies in situ ; and that the fungus which produces the potato disease

is aquatic in one stage of its existence, and in that which the leaf is constructed. When these hairs and stage the resting spores are formed.

cells are compared with the fine thread at c, which Reference may here be made to the bodies found represents a branch of the potato fungus coming out germinating in the intercellular passages of spent of a breathing pore of the leaf, it will be seen how potatoes by Dr. Montagne (Artotrogus), and re very minute the fungus is in comparison with the ferred by Mr. Berkeley to the Sepedoniei. Ever dimensions of the leaf. This fine thread is no other since Mr. Berkeley first saw these bodies he has than a continuation of a thread of spawn or mycehad an unswerving faith in the probability of their lium which lives inside and at the expense of the being the secondary form of fruit of Peronospora assimilated material of the leaf. When this thread infestans, but unfortunately, as far as I know, no emerges into the air, as here shown, it speedily one has ever found a specimen of Artotrogus since ramifies in different directions, and bears fruit at the Montagne.

tips of the branches, as at DD; these fruits are The question may, therefore, be naturally asked, - termed simple spores, or conidia, because from their How does Artotrogus agree with the presumed smallness they are dust-like. It is quite possible resting spores here figured and described ? And they may be an early state of the vesicles which conhas Mr. Berkeley been right or wrong in clinging tain the zoospores, as seen at E, F. However this so tenaciously to his first idea? Fortunately for may be, they are commonly arrested in growth when the investigation of the potato disease (which can still small, and they germinate in an exactly similar never be cured till it is understood), Mr. Berkeley manner with the zoospores themselves, and may be has given in the Journal of the Royal Horticultural considered somewhat analogous with seeds. The Society the number of diameters his figures are potato fungus has another method of reproducing magnified to, and I have here engraved those figures itself in the “swarm-spores” shown at e, f. These so as to correspond in scale with my own drawings, are so called because, on the application of moisture which latter are sketched with a camera lucida. (as supplied by dew or rain, or when applied It will be seen that they are the same with each artificially), the vesicles set free a swarm of from other both in size and habit, with the exception of six to fifteen or sixteen other bodies known as the processes on the mature spore of Artotrogus "zoospores,” so named because they are furnished which processes may possibly be mere mycelial

with two lash-like tails, and are capable of moving threads, or due to the collapsing of the inflated rapidly about like animalcules. This rapid moveepispore. The reason why these resting spores have ment usually lasts for about half an hour, and (like evaded previous search is that no one has thought the dust-like conidia or simple spores” before of finding them amongst leaves which had been / mentioned) the swarm-spores generally enter the macerated for a long period in water. There is, breathing pores of the leaf, and there germinate. however, nothing unreasonable in fruit being per So potent, however, are the contents of these bodies fected in water or very damp places, as it is common

when set free, that they are capable of at once corin the Saprolegnieæ and amongst Algæ in general. i roding, boring, and entering the epidermis of the To sum up, there are four reasons why the bodies | leaf, or even the sten or tuber itself. These here described belong to the old potato disease: zoospores are best seen when within the vesicle P,

1. Because they are found associated with the where they arise from a differentiation of the conPeronospora and upon the potato plant itself. tents, but when once set free (G) they are, from the

2. Because they agree in size and character with extreme rapidity of their movements, very difficult the known resting spores of other species of Perono

to make out. In about half an hour they cease to spora.

move, their lash-like tails (cilia) disappear, and 3. Because some other moulds are aquatic in one having burst at one end, a transparent tube is prostage of their existence.

truded, which is a similar mycelium in every respect. 4. Because they agree in size with Artotrogus. with that produced by the simple spore, and which

Now that these drawings illustrative of the grows, branches, and fruits in a precisely similar fungus which causes the potato murrain are reproduced in the following plates, it may be as well to Now the great difficulty which has beset botanists explain at once some of the terms used and the for so many years bas been to account for the winter nature and habit of the bodies hereafter referred to, life of the potato fungus. Simple spores and zoofor such readers as may not be thoroughly acquainted spores are lost in the production of the mycelium or with the life history of the destructive parasitic spawn, and this latter fine thread-like material moulds to which the potato fungus belongs. For cannot of course survive the frosts and rains of that purpose reference must be made to fig. 159, winter, but must utterly perish with the perished which shows (greatly enlarged) a transverse section leaves and haulm.

A

ospora allied to bodies at A a represent two minute hairs on the the one which produces the potato disease, reveals leaf, and at B B are seen the individual cells of the fact of a third mode of reproduction. Simple

manner.

are

as

spore - like

spores and zoospores

termed asexual, because they are without sex,

distinguished from other bodies called oospores, which are produced by the contact of two sexual bodies, known as the antheridium, which is the male, and analogous with the anther, H, and the oogonium, the female, and analogous with the ovary of a flower,j. The

oospores, not till now seen for certain in the potato disease, are the true resting spores.

Instead of being transparent and unenduring, as are the simple and zoospores, these bodies are at length dense in substance, black-brown in colour, and covered externally with reticulations or warts. Tbey are produced from the mycelium, by the contact of the antheridium and oogonium in the substance of the decay. ing plant; they are washed into the earth, and there they rest till a certain set of conditions makes them ger. mipate in the year following their production, just as a seed falls and rests in the autumn and starts again into life during the following spring.

The terms here used will be better understood if the following note is borne in mind : The oogonium is analo. gous with a pod, the

Fig. 159. Transverse Section of a Fragment of Potato Leaf with Peronospora infrotuns. oosphere within

Enlarged 250 diameters. swers to the ovule, and the oospore (or resting spore) is the matured seed. | fungus these resting spores have been seen, meaThe antheridium with its contents is analogous sured, and illustrated, but till now the resting spore with the anther and its pollen.

of the potato fungus has eluded all search. The In various other fungi nearly allied to the potato reason generally given and accepted for its absence

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