18 SUMMARY OF CURRENT RESEARCHES RELATING TO 



It gradually progressed, and in eight months defecation and mictu- 

 rition were accomplislied as in healthy adults. Fourteen months after 

 bein^ injured, these dogs were killed and examined. The several 

 portions of the cord were found united by copious cicatricial con- 

 nective tissue, within which numerous nervous fibres appeared. No 

 ganglionic corpuscles could be seen. 



It is further notable that in such injured dogs, as well as in frogs, 

 the return of motility precedes that of sensibility. 



Spinal Root of Optic Nerve.* — Dr. J. Stilling recommends his 

 method of teasing asunder nervous strands (Zerfaserungsmethode), 

 which comes greatly in aid of transverse sections. By this method 

 he has demonstrated, macroscopically, the presence of a descending 

 optic tract, one of whose bundles he traces back as far as the decussa- 

 tion of the pyramids. Through this path its spinal course must 

 follow. 



Thus the views of Goltz, arrived at by way of experiment, are 

 supported. Many details as to the human optic chiasma and its con- 

 nections are given. The whole will be published elsewhere at greater 

 length. 



Retinal Vessels of Fishes.f — How are we to explain the contra- 

 dictory statements about the presence of vessels in the retina of 

 fishes ? H. Miiller, J. Hyrtl, and Max Schultze denied the existence 

 of such vessels. W. Krause and, more briefly, W. Miiller described 

 them in the eel. Most of the other authorities are silent on this 

 subject. 



Dr. G. Denissenko now shows how vessels are distributed in the 

 retina of the carp. They occur not only in the innermost layers, but 

 also in the outer granular layer. A figure, from a design by 

 Dr. Heitzman, representing a section through the retina of a young 

 carp, is appended to this paper. 



In the adult carp the vessels are insignificant, and might very 

 easily be passed over. In old eels Dr. Denissenko could not see any 

 vessels. He thus corroborates the opinion of W. Krause, that with 

 age these vessels usually disappear, in consequence of the growth of 

 the eye forwards and sidewards, and the simultaneous extension of 

 the optic nerve. In this way the vessels become compressed ; their 

 lumen is reduced, and finally obliterated. 



True Origin of the Acoustic Nerve.J — Herr C. F. W. Roller 

 describes the course of ascending spinal fibres for the auditory nerve. 

 On the same subject we have also a short notice by R. Wiedersheim.§ 

 Herr Roller promises further details. 



Auditory Ossicles of Mammals.|| — One of the most pressing 

 questions in comparative craniology is what are the true homologies 

 of the small ear-bones of mammals ? Professor W. Salensky, from 



* Arch. Mikr. Anat., xviii. (1880) pp. 468-80, figs. 1-4 of a pi. 



t Ibid., pp. 480-85 (1 fig. of a pi.). J Ibid., pp. 403-8 (1 pi.). 



§ Zool. Anzeig., iii. (1880) pp. 495-6 (1 fig.). 



11 Morph. Jahrb. (Gegenbaur), vi. (1880) pp. 415-32 (1 pi.). 



