The preservation of blood absolutely unchanged in appearance is essential to a successful study of its structure. Hitherto the inadequacy of most students' microscopes and the necessity for immediate and hasty inspection of blood has almost prevented its successful study. To these reasons it should be added that only the few students who make somewhat of a specialty of this branch of science can become sufficiently expert for its more difficult investigations; and the author's estimate of drying as a means of preserving blood, that it is of little or no use, meets with an important exception in the case of studies as to the class of animals to which a given specimen of blood belongs, and also in the determination of the existence of certain diseases. For all purposes, however, it is desirable to preserve the corpuscles in their natural state, and osmic acid has been successfully introduced for this purpose by Prof. Max Schultz. A film of blood on a glass cover is exposed for three minutes to the vapor arising from a bottle of two per cent. solution of osmic acid; after which it may be immediately mounted in a nearly saturated solution of acetate of potash. "Every corpuscle thus becomes set,' as it were, in its living form."

A New GROUP OF INFUSORIA. — In studying the blood of frogs Mr. E. Ray Lankester has sometimes noticed a little parasite which was at first mistaken for a very active white blood-corpuscle. This new infusorian, which is figured in the "Quarterly Journal of Microscopical Science" for October last under the name of Undulina ranarum, is a minute pyriform sac, the narrower end of which is somewhat twisted and spirally bent round upon itself, giving it a strikingly shell-like appearance. It has neither mouth nor cilia, but instead of the latter a broad, toothed, undulating membrane which makes it the type of a new group of infusoria.

STRUCTURE OF MINUTE ORGANISMS.-The "New York Evangelist." in describing with very natural admiration the beautiful Moller's Type Plate (the diatoms of which, by the way, are undoubtedly vegetable and not animal organisms), raises again the question whether these minute organisms may not be possessed of organs and tastes corresponding to those of higher aminals. Persons having an intelligent interest in the science of microscopy, but unfamiliar with its details, cannot be too well assured that the extreme simplicity of the lower organisms is a fact of positive,

not of negative, knowledge, -a conclusion reached from what we see, and not from what we fail to see.

PURE WATER.-Dr. Burdon Sanderson, F.R.S., found it impossible to obtain optically pure water. The fusion of ice furnished the nearest approach to this standard.

RAILWAY DUST. - The "Manchester Guardian" publishes a study of railway dust made by Mr. J. Sidebotham, who finds it to consist, in the case examined, about one-half of particles of iron, and the other half of cinders, sand, etc. Some of the particles of iron were magnetic, and most were sharp, rough and irritating.

NOTES.

WE make the following extracts from a letter to one of the editors from Mr. Dall, Chief of the Coast Survey Expedition to explore the hydrography and natural history of Alaska. It is dated Harbor of Iliuliuk, Unalashka, Alaska Terr., Oct. 30, 1871:

"We arrived here on the 23d of September after a disagreeable passage of twenty-six days from San Francisco, during which, however, we obtained some very interesting observations on the currents. We have been very busy since we arrived, and have accumulated abundance of material to keep us busy all winter, both in regard to Natural History and Hydrography. This harbor is a fine one, and we have a chart well under way and hope by spring to have it approximately complete. Tidal and current observations are going on, we have taken many hundreds of angles and shall go to sounding bye and bye.

The island when we came was a mass of verdure up to the snow caps of the highest peaks. There are no trees, except half a dozen planted by Veniaminoff, the apostle of the Aleuts, in 1805. They are Sitka spruce, very stout and thick, but only about fifteen feet high. The indigenous shrubs and willows are seldom more than six feet high and an inch or two thick. I went on an exploring trip the other day in the interior of the island and with the exception of some wood which we packed on our backs for kindling, we had to boil our tea with green huckleberry bushes! But the herbage is very rich and rank. Sheep and pigs do exceedingly well here with less care than they need at home and I believe hardy cattle would do the same. The winter is wet and windy, but not cold; there is a good deal of snow but it melts very quickly after it falls and rarely lies on the ground any length of time except in severe seasons. The waters abound with fish but there are no land animals, except spermophiles and foxes. Whales are very

often seen inside the harbor. Birds are rather plenty at this season and probably much more so in summer.

It has not been

This month and the next are the worst of the year. We have had more or less rain almost daily, but also a good deal of sunshine, more indeed than I anticipated. The weather has been comfortable, temperature averaging 44° Fahr. lower than 32' yet and that only once, still the snow has crept down the mountain sides a thousand feet and we have had several real old fashioned snow storms.

All hands have worked together harmoniously and with energy. I think the prospects for a good season's work are very favorable.” –WM. II. DALL, Acty. Asst. U. S. C. Survey.

T. STERRY HUNT, LL. D., chemist to the Canadian Geological Survey, has been appointed to the chair of Geology in the Massachusetts Institute of Technology.

SOME One writes to "Land and Water" that though the menagerie at the Jardin des Plantes is at a low ebb, still specimens are being forwarded by the various agents with all speed, and we may hope soon to see it with some of its former glories.

PROF. C. F. Hartt has recently returned from his explorations in Brazil, having specially studied the supposed Amazonian drift beds; and Prof. Marsh has returned to New Haven, with immense collections of fossil vertebrates, etc., from the Rocky Mountains.

PROF. II. James Clark, of the University of Kentucky, has been appointed Prof. of Veterinary Science in the Massachusetts Agricultural College.

DR. G. Hartung, the well known geologist and author of the splendid works on Madeira, Lancerota, Teneriffe and the Azores, has recently made a geological trip through this country, so as to be able the better to study American works on geology. We also learn from Prof. Hagen that two other German geologists of good reputation, Drs. Reiss and Stuebel, authors of works on Teneriffe, and Santorin, have been geologising for two years past on the west coast of South and Central America, and travelling thence from New York to California, design to go to the Hawaiian Islands to investigate their geology with a view to publication.

How interesting a collection illustrating the products, habits and homes of insects, as well as the relations of zoology and botany to agriculture and the arts may be, is to be seen in a visit to the Museum of the Agricultural Department at Washington, the

result of many years' work of Mr. Townend Glover, to whose unrequited labors in practical entomology we have previously called attention.

He has a beautifully illustrated manuscript work on the insects injurious to cotton and other crops, which thus far Congress has been asked in vain to publish. To the great value of the museum Prof. Hagen of the Museum of Comparative Zoology at Cambridge bears the following testimony. "I find no notice in the NATURALIST of the Museum of the Agricultural Department in Washington, D. C., the admirable work of Mr. T. Glover. I was really astonished at going through this valuable collection. The plan upon which Mr. Glover works is his own, and the arrangement of his own devising. When fish, fruits, etc., cannot be preserved, excellent casts beautifully colored are made and exhibited. Plates illustrating injurious and beneficial insects and their transformations, drawn, engraved and colored with his own hand, are mounted in the halls,so that if any one wants to know about the insects injuring certain crops or plants, he can obtain very complete information. I know not which the more to admire, the extensive, really vast plan of the institution, and the elegant completion of the design, or the modesty of the learned naturalist who has conceived and done it all entirely without aid, in the agricultural interests of this great country; meanwhile supported by means really ridiculously small, compared with the results. I confess that the Agricultural Museum in Washington has no superior in the world, and even no rival either in England, France or Germany.”

THE authorities of Brown University are beginning to form a museum of natural history. During the last year several additional large cases were placed in Rhode Island Hall, and between three and four hundred specimens of birds and animals were added to the previous collection. A large collection of the implements of American Indians was also added, together with several small though valuable collections of coins, both ancient and modern. The expense incurred by these improvements was met by a few friends of the College, interested in this department. Arrangements have now been made for adding to the Cabinet an extremely valuable collection of birds, numbering about forty-five hundred; and also such specimens in Mammalogy, Herpetology, Ichthyology, Conchology and Comparative Anatomy, as will meet the wants of instruction.

The mounting and arrangement of the specimens is entrusted to the care of Mr. J. W. P. Jenks, A.M., a well informed practical naturalist, and a most skilful taxidermist. Mr. Jenks was one of the party assembled by Prof. Baird, U. S. Fish Commissioner, at Wood's Hole, during the last summer, and spent six weeks in making full collections of the marine animals of that coast, so that this department usually so incomplete in our colleges, will be well represented at Brown.

AMONG the losses sustained by the burning of the Museum of the Chicago Academy of Sciences was that of the State collection of insects, recently purchased by the State from the heirs of the late State Entomologist, Mr. B. D. Walsh, for two thousand dollars, but of great scientific value from the number of types it contained.

"The Smithsonian collection of Crustacea, undoubtedly the largest alcoholic collection in the world, which filled over ten thousand jars, and contained the types of the species described by Prof. Dana and other American authors, besides hundreds of new species, many of which were described in manuscripts lost by the same fire.

“The invertebrates of the United States North Pacific Exploring Expedition, collected in great part in Japanese seas by the Secretary in 1853-56, which, besides crustacea, included in the last item, embraced great numbers of annelides, mollusca, and radiata, most of which remain undescribed, except in manuscripts also lost.

"The collection of the marine shells of the coast of the United States, made by the Secretary and his correspondents during twenty years of dredgings and general research on every part of the coast from Maine to Texas. Nearly every species was illustrated by specimens from every locality in which it occurs, not only on our own shores, but on those of Europe and the Arctic Sea, and in the Tertiary and Quaternary formations, showing the effect of climatic influences, geological age, etc. This collection embraced about eight thousand separate lots of specimens.

"The deep-sea crustacea and mollusca dredged in the Gulf Stream by M. Pourtales, of the United States Coast Survey, in the years 1867, '68 and '69, which had been placed in the hands of the Secretary for description.

"The manuscript of the Invertebrate Zoology of the North Pacific Exploring Expedition under the command of Capts. Ringgold and Rodgers, in 1853-56; the shells by the late Dr. A. A. Gould ; the Crustacea, Annelida, Nudibranchiate and Tunicate Mollusca, Holothurians and Starfishes, by Wm. Stimpson. These manu

scripts were illustrated by nearly three thousand drawings by A. Schoenborn and W. Stimpson, many of which were colored. This material was awaiting an appropriation from Congress for publication. A portion thereof (that on the Brachyurous Crustacea) was