318 PROGRESS OF MICROSCOPICAL SCIENCE. ["J^rnl'l. jS'TsVa' 



This, wliicli we have termed the germ, or egg-cell, and which we 

 regard as the first coll of the embryo se forme imrtout tie la meine 

 maniere ; it always presents the same characteristics and produces 

 by division the first cells of the embryo. But the vitellus of the egg 

 is composed of two elements ; the one, the protoplasmatic, repre- 

 sents the substance (corps) of the egg-cell ; the other, the nutritive, 

 forms what we have called the deuto-plasm of the ovum. This 

 deuto-plasm is the accessory part of the vitellus ; it is sometimes 

 absent, arises in various ways, presents un-uniform relations to the 

 protoplasm, and undergoes very different operations in the course 

 of the first embryonic phenomena." M. Van Beneden's treatise 

 is one which should be in the library of every student of natural 

 science. 



PKOGEESS OF MICROSCOPICAL SCIENCE. 



The Belation between Ascidians and Vertebrates. — This important 

 fact, which was mooted a couple of years since, seems to be better 

 established every day. In the last number of Max Schultze's ' Archiv ' 

 (Band VI., Heft 2) Professor Kiipifer, of Kiel, has a very imjiortant 

 paper on the subject, illustrated by three exquisite plates detailing the 

 development of Ascidia canina. The memoir will well repay careful 

 study. 



TJte Ganglion-bodies of the Cerebrum. — Dr. Rudolf Arnt, of Griefswald, 

 contributes to the above journal a very valuable paper " On the Structure 

 of the Nerve-cells of the Brain." He esioecially describes the peculiar 

 ganglion-cells whose prolongations, several in number, can often be 

 traced to a considerable distance, thinning out and ending in exquisitely 

 delicate filaments, which are covered with minute globular particles 

 attached to them almost as grapes are on a stalk. 



Terminations of the Nerves in the SMn. — Herr C. J. Eberth, who has 

 been working at the problem of the mode of termination of the nerves 

 in the skin, has published recently the results of his inquiries, especi- 

 ally with regard to the skins of dogs and cats. Many of his prepara- 

 tions were made with the chloride of gold solution, and they lead him 

 to believe that the nerve filaments jiass even beyond the papilla, and 

 apparently travel through the basement membrane and into the epider- 

 mis. The gold solution, however, is possibly a dangerous one for 

 inquiries of this delicate kind, and it certainly seems as if Herr Eberth's 

 drawings were capable of another interpretation than that which ho 

 puts uj)on them. — Schultze's Archiv, Band VI., Heft 2. 



A New Microtome, which will interest some of our readers, is de- 

 scribed in the last number of Max Schultze's ' Archiv,' by Herr W. His. 

 Its construction is too elaborate to be described without the aid of the 

 woodcuts contained in the paper. Its cost is aboiit 6Z. 



