76 PROGRESS OF MICROSCOPICAL SCIENCE. 



the cells are composed of two walls, the outer green (or otherwise 

 coloured), composed of laminated cells, the inner white and structure- 

 less. Upon puncturing the plants a liquid is forcibly ejected. I have 

 never been able to discover the contained cells for want of a good 

 microscope. By placing the cake of earth sent you in a plate, and 

 adding water enough to make it of about the consistence of potter's 

 clay, and keeping it at a temperature about 60°, you will find a fresh 

 crop of the plant to develop, and you will thus nave an opportunity 

 of studying them." — Grevillea, Dec. 1872. 



The Structure of the Nerve Fibres. — In the ' Centralblatt,' * Dr. 

 Tamamschef gives the results of his researches on this point, which 

 have been recently translated in the ' Lancet,' | which we may 

 mention usually contains, of late, something of interest to the micro- 

 scopist. Dr. Tamamschef 's specimens have chiefly been taken from 

 the lumbar, sciatic, and brachial plexuses of man and of the 

 mouse. Those from the latter, immediately after their removal 

 from the living body, were plunged either into distilled water or into 

 serum or the aqueous humour, and examined with high powers. Many 

 nerve tubules, he finds, are united together and enclosed by a common 

 sheath composed of flat shells, which may be brought into view by a 

 solution of nitrate of silver. This sheath probably belongs to the lym- 

 phatic system. The nerve tubules are composed of an external sheath 

 or neurilemma, the white substance of Schwann, and the axis cylinder. 

 On the careful addition of ammonia and then of acetic acid to the 

 nerves on the stage of the microscope, it may be shown that the cylin- 

 der axis is composed of a completely homogeneous matrix, which dis- 

 solves readily in ammonia, and in which spheroidal bodies gradually in 

 about three-quarters of an hour make their appearance, which he pro- 

 poses to term nerve corpuscles — corpuscula nervea. The corpuscles are 

 in contact with one another throughout the whole length of the tube, and 

 are capable of spontaneous movement ; their size is nearly equal to that 

 of the red corpuscles of the blood, and they may with cautious manipu- 

 lation be obtained altogether detached from the nerve tubules under 

 the influence of various reagents ; they break up into minute granules, 

 which exhibit Brunonian movements in oil of turpentine. In order 

 to determine whether the cylinder axis belongs — as is usually thought 

 — to the albuminous compounds, M. Tamamschef undertook a compa- 

 rative series of micro-chemical investigations between fresh albumen 

 and these cylinder axes. He finds that pure albumen, in the course of 

 two or three days, exhibits the same kind of resolution into spheroidal 

 elements, more or less nearly approximating in size those of the 

 cylinder axis. After the addition of alkalies and acids, however, the 

 similarity is no longer perceptible. Alkalies, and especially ammonia, 

 cause the corpuscles to swell up, and several granules make their 

 appearance, which are capable of moving in a concentric manner; 

 sometimes a triple zone appears, of which the internal appears red- 

 dish, the middle greenish blue, and the external dark-violet. Acids 

 cause the muscles to shrivel, and finally to break up into numerous 



* No. 38, 1872. t December 14, 1872. 





