treated by soakage in full strength sulphuric acid of commerce, germinated without failure.

Two sets of old and hard Australian tree-seeds were planted, one set having been severely treated with acid, full strength.

There was a marked difference in the time of germination between the treated and untreated seeds. All of the treated seeds germinated within one month, while the non-treated did not germinate until the expiration of three months after planting. Beans were so severely treated that their hulls separated and shrivelled up, yet all germinated and grew vigorously.

A palm-seed measuring 24 inches long by 14 inches across, and as hard as vegetable ivory, was soaked in a mixture of sulphuricacid, diluted with fifty per cent. of water for a period of twentyfour hours, and to render the soakage the more complete, the shell of the nut at the base end was removed to the extent of half an inch in diameter superficial measurement.

This seed germinated three weeks after planting, although the usual period of germination of the seed under hot-house culture is sometimes several years. Seeds which ordinarily germinate in a short period of time are not improved by the acid treatment, as far as my experiments have gone. Its utility has been most conspicuous in the case of cotton-seeds and hard and old tree-seeds, including palm-seeds.

It is my present purpose to continue my experiments with seeds, and any useful results that may be attained will be made known to the public in the Reports of the Department of Agriculture or other publications. In the meantime, it is my intention to have treated cotton-sceds tested in the open fields in the coming season on a scale sufficiently large to ascertain practically the benefits of the sulphuric-acid treatment.

The following extract from a letter from a practical cotton planter, formerly of North Carolina, sets forth clearly the possible advantages to be derived by the planter from cotton-seeds thus treated: :

WASHINGTON, D. C.

24th July,

1880.

MR. THOMAS TAYLOR,

Microscopist, Department of Agriculture.

DEAR SIR:

I know something about the raising of cotton, having spent the greater part of my life in Cabarrus County, North Carolina, where cotton is our money crop.

Your discovery of removing the lint from cotton-seed without injuring the germ is of great value.

In the first place: as you prepare them, the seed can now be drilled at regular intervals apart, as easily as grains of corn, and this will, to a great extent, if not entirely, do away with the labor of thinning out the weed known among planters as "chopping cotton." This regular drilling was not possible by any machine while the seed was coated with lint, for the lint held the mass together, so that the individual grains could not be separated.

In the second place: the seed, as you prepare them, come up much earlier than what we may now call "lint-seed."

This makes them doubly valuable to the planters of the Northern belt of the cotton region, where the frost so often catches the crop, cutting it down, not unfrequently one-third. The earlier start of the prepared sced will much reduce the damage now done by the frost.

Yours truly,

WM. M. COLEMAN.

PERMANENT MICROSCOPIC PREPARATIONS OF PLASMODIUM. By SIMON H. GAGE, of Ithaca, N. Y.

THE previously published methods of making permanent preparations of the motile or naked protoplasmic stage of the Myxomycetes are but two, so far as I know; and no method of getting the Plasmodium in a desired position has to my knowledge been published.

The old method was to dry the extended Plasmodium, the new is to harden it with osmic acid. Both these methods are defective, for osmic acid changes the color of the protoplasm, and drying causes it to shrink as well as to change color.

The following is a simple and efficient method of extension and preservation: Small pieces of the rotten wood, on which the Plasmodium is found, should be placed on moistened microscope slides with some of the Plasmodium touching the slides. These should be on a piece of window or plate glass, and over the whole should be placed a bell-jar, or other cover, to prevent evaporation. After an hour or more, the glass on which the slides rest should be lifted up to see whether the protoplasm has crawled out upon any of the slides. If any of the slides are satisfactory, lift off the bell-jar and remove the pieces of wood from the slide. The

Plasmodium will remain. The slide should then be put very gently into a mixture of equal parts of a saturated aqueous solution of picric acid and 95 per cent. alcohol; it should be removed in 15 or 20 minutes, and placed, for about the same length of time, in 95 per cent. alcohol; it may then be mounted in Canada balsam in the usual way, but without previous clearing.

The picric acid stiffens the protoplasm almost instantly, but does not shrink it, the alcohol removes the water and allows of Canada balsam mounting.

The above method is especially good for the yellow Plasmodium, as the color is precisely that of the picric acid solution. If white Plasmodium is to be mounted it should be soaked in 25 per cent. alcohol to remove the yellow color of the picric acid, before anhydrating it with strong alcohol.

Experiments have not been tried with Plasmodium of purple and other colors to determine successful methods of preservation, but some slight modification of the above is confidently expected to succeed.

SUMMARY. A.-The Plasmodium will crawl from rotten wood and extend itself on a moistened glass surface.

B. The extended Plasmodium may be fixed in position by immersing the slide on which it is extended in a solution of picric acid.

C. The slide may be placed in 95 per cent. alcohol to anhydrate the Plasmodium, after which it may be mounted in Canada balsam.

D. The yellow Plasmodium retains its natural color if treated in this way.

PERMANENT MICROSCOPIC PREPARATIONS OF AMPHIBIAN BLOOD CORPUSCLES. BY SIMON H. GAGE, of Ithaca, N. Y.

THE very excellent method of drying the corpuscles of mammalian blood, on the microscopic slide, is not applicable to the much more bulky corpuscles of Amphibia. The corpuscles of the latter are sure to be distorted and seamed in drying; hence various methods of preserving the corpuscles moist have been tried with varying success.

The following very great modification of the method proposed by Ranvier, in his treatise on histology,1 has been in uge for some time in the Anatomical Laboratory of Cornell University, and has given uniformly excellent results. Preparations made three years ago are quite as good as at first.

Three or four drops of fresh blood are allowed to fall into 10 cc. of normal salt solution (common salt 750 milligrammes, water 100 cc.), preferably contained in a high narrow vessel like a graduate glass or beaker. The mixture of blood and salt solution should be well agitated and then 100 cc. of a saturated aqueous solution of picric acid added with constant stirring. After the corpuscles have settled, as much of the supernatant liquid as possible is poured off, and in its place is put about an equal volume of normal salt solution. The corpuscles are allowed to settle, the liquid poured off and another volume of salt solution added. This is continued until the salt solution acquires only a faint yellow tinge.

The use of the salt solution is, first, to dilute the blood in order to avoid distortion of the corpuscles, and second, to wash away the picric acid so that the subsequent staining will be more satisfactory.

After pouring off the last salt solution, there is put in its place 10 cc. of a mixture of five parts of Frey's carmine and ninety-five parts of picrocarmine. The corpuscles will stain in from one to fifteen hours. A drop of the agitated mixture should be examined occasionally to ascertain when the staining is sufficient. The nucleus should be deep red, and the body of the corpuscle yellow or pinkish.

When the staining is completed, as much stainer as possible should be poured off, and replaced by 10 or 15 cc. of acid glycerine (glycerine 100 cc., acetic or formic acid 1 cc.). This mixture of corpuscles and glycerine may be placed in a bottle and used at any time, it being simply necessary to agitate the mixture slightly or to take up some of the sediment with a pipette and mount it precisely as any other glycerine preparation.

Summary.-1. The fresh blood is first diluted with about fifty times its volume of normal salt solution.

2. To this diluted blood is added ten times as great a volume of a saturated aqueous solution of picric acid.

1 Traité technique de Histologic, p. 195.

3. The picric acid is washed away with normal salt solution. 4. The corpuscles are stained with picrocarmine, or a mixture of this and Frey's carmine.

5. They are preserved in acid glycerine, and may be mounted for the microscope at any time.

METHOD OF PREPARING AND MOUNTING WINGS OF MICROLEPIDOPTERA. By C. H. FERNALD, of Orono, Me.

FOR a long time I have been seeking some method, by means of which, the wings of the microlepidoptera could be prepared, so that the venation could be studied under the compound microscope, in a manner that would leave no doubt of the presence, or absence, of the faintest vein in the whole wing-structure.

The removal of the scales by mechanical means, as resorted to by some, was to me quite unsatisfactory, and, in some cases, even impracticable. I therefore tried some of the methods recommended for bleaching the wings of small moths. That described by Chambers, in the Canadian Entomologist, was not a success in all cases, but whether not properly tried, I cannot say.

I next tried the method for bleaching the wings, published by Dimmock, and while this seemed to be a success so far as the bleaching was concerned, the final mounting did not always give satisfactory results; for when mounted dry, the scales, although bleached, were not sufficiently transparent to show clearly the more obscure parts of the structure, and when mounted in Canada balsam, the entire wing was rendered so transparent that only the larger veins were visible, and I found it extremely difficult to get rid of the air bubbles, which so readily gathered under the concave portions of certain minute wings.

I next tried mounting in cold glycerine. After having been bleached by Dimmock's method, the wings were transferred to the slide direct from the water in which they were washed, then allowed to dry, which was sometimes hastened by holding the slide over the flame of a lamp. When quite dry, a drop of glycerine was added and the cover at once put on, and where the