groups of three to six grains; various shapes of the grains are shown in fig. 21. These grains have a peculiar rough look on the surface which it is difficult to represent in a drawing. Different parts of the root differ somewhat in structure, as the starchgrains of one part are smaller, lighter colored, and smoother (fig. 22 a), while some portions, probably of the bark, exhibit cells of an oblong, rectangular shape, with finely punctate cell-walls (fig. 22 6). The spiral vessels are large and coarsely marked (fig. 23), and some of them appear nearly square. In all the samples of turmeric that I have examined, more or less starch from other plants was found, usually consisting of rice-starch (fig. 24 b) and wheat-starch (fig. 23 c) but in some samples I found also a large-grained starch (fig. 24 a) probably of some kind of arrow-root, or else from the white roots of turmeric, as this is sometimes sold as arrowroot. These granules are as colorless as wheat-starch, polarize with narrow bands, yet wider than potatostarch, and are somewhat less quickly dissolved by potash, but finally dissolve almost completely (fig. 27 b).

The yellow grains of the turmericstarch are quickly and deeply stained by iodine as any other starch, but do not show so clear a blue color on the addition of sulphuric acid as do the whiter starches. The starch (fig. 22 a) gives a very deep clear-blue color by this process. Potash swells the yellow turmuric-starch to several times its former bulk, but the shape is still preserved and the sack-like membrane of the starch-grains remains visible even when heat is used (fig. 27 a). The yellow grains of turmeric-starch do not polarize in my hands with or without selenite. A quantity of thin, colorless, irregular scales, exhibiting no trace of structure (fig. 25) are seen in ground turmeric, but their origin is uncertain. The earthy adulterants consisting of small masses of aggregated granular particles (fig. 28) which separate by pres

Billroth believes that all forms of bacteria are but different stages in the growth of a single organism, which he names Coccobacteria septica. He supposes that this organism exists in two forms, viz. the coccusform, when it appears as minute, round cells, and the bacteria-form when it is elongated or rod-shaped. He then distinguishes the different forms by their size. The coccusforms are named micro-, mesa- and mega-coccus; the bacteria-forms are

* Abstract of some remarks by the President before the New York Microscopical Society, January 6th, 1882.

Motion of Diatoms.

The article in the last JOURNAL from Dr. Geo. M. Sternberg, confirming Dr. Wallich's view relative to the motion of Diatoms, is interesting to all who have studied the subject. He says: "Dr. Wallich ascribes these motions to the existence of prehensile filaments capable of alternate extension and retraction, of extreme tenuity, yet of extraordinary strength and elasticity." Dr. Sternberg has not been able to see these filaments in living diatoms, and therefore cannot verify the assertion. His method of instantly terminating the life of diatoms is both interesting and unique; but, judging from the instantaneous contraction which has taken place in the many animal and vegetable objects which I have attempted to prepare for mounting, I am surprised that he succeeded so well. About

eight years ago I was in correspondence with Prof. H. L. Smith concerning the motion of diatoms, when he called my attention to certain filamentous growths, hairs, or pseudopodia, long and very slender, proceeding from the edge of Stephanodiscus Niagara. Sometimes they were twice as long as the diameter of the diatom. No one had seen them but himself at that time, and he had only observed them two or three times. In a few weeks I was gratified by finding the same attachments in a gathering which I made from the water-supply from Niagara River.

I still have some of them mounted on a slide which shows them very distinctly. In 1876 I sent the slide, with others, to microscopists for their examination and opinion as to the nature of the filaments. Those of them who ventured an opinion were inclined to consider them pseudopodia. I quote from one correspondent, Mr. Geo. W. Morehouse, who says: "Certainly there is strong resemblance to pseudopodia. Did you detect any motion of the pseudopodia while the diatoms were living?

** *

On the whole the resemblance to pseudopodia is greater than to anything I know of. Plants do not possess true pseudopodia, but, in the lower forms, are there not some families of plant-animals, possessing some characteristic of both animal and plant? Is it possible in all cases to distinguish between protoplasm and sarcode?

* * * I consider your discovery of considerable importance, and hope you will give the facts to the public." I have not done this, except as above indicated and also by showing the slide to a few individuals. I have been waiting for more light. Now, if Dr. Wallich and Dr. Sternberg have been able to photograph or prepare diatoms in any other way, showing any indications of these filaments, whether prehensile or not, it would give me great pleasure to have an opportunity to compare their specimens with mine. For my

own part, I have been inclined to regard the filaments as a parasitic fungus, but this may be far from the truth. There is one fact, however, that must be borne in mind, viz.: that Stephanodiscus, like all the discoidal diatoms, has very little motion, if any. Then, what are the filaments for, if they are a part of the diatom? I have observed another point of great interest in the study of this subject, and it may ultimately help to throw light on it. In my continued examination of the diatoms found in the Niagara water-supply, I have at times found the smaller discoidal diatoms, such as Orthosira, Melosira, and some of the genus Cyclotella, in great abundance. These were stationary, of course; but on the slide, under the cover-glass or not, they would repel every light-body, and all the debris from contact with them, so that a distinct annulus, clear and well defined, would be formed around them. The width of the annulus was about equal to the diameter of the frustule. This phenomenon may be witnessed by any who are so fortunate as to collect this

readily add benzole ; and in case the cell becomes rough, dip the brush in clear benzole and smooth it. Use a brush well filled with the cement to secure a smooth background. With a little practice a person may easily make fifty beautiful and practical white cells in one evening, and in a few hours they will be hard and ready for use. When the cover-glass is to be fastened a little of the cement is easily applied. When dry the slide may be finished with colors prepared from tube paints mixed with benzole-balsam, or with damar and benzole. Before mounting, if a dark background is desired, I know of nothing better than a disc of asphalt of any desired size turned in the centre of the ring. Over the asphalt a small sized cover-glass may be used for the object to be placed upon, or the asphalt may be covered with shellac when dry. The object may be fastened with gelatin or gum arabic, or made to adhere to the coat of shellac before it becomes dry.