157 



only ones which I have demonstrated in connection with the anterior 

 group of spindle cells. 



In a number of minor points Tretjakoff has misunderstood or 

 misrepresented the statements of the present writer, perhaps through 

 an imperfect understanding of English. These may be briefly noted. 



On p. 655, lines 14 to 17, the author cites me as describing a 

 continuity of the lobus vagi with the cerebellum. In fact, the most 

 important thing which I demonstrated in my paper (1902) was the 

 continuity of the acusticum with the cerebellum, while the lobus vagi 

 has no relation with the cerebellum. The demonstration of the fact 

 that the cerebellum has been developed out of a certain segment of 

 the dorsal (somatic) sensory column of gray matter is one of the chief 

 contributions of the present writer to comparative neurology (see 1901, 

 1902, 1902a, 1906, 1909). 



The criticisms on page 662—3 beginning "Die Befunde von John- 

 ston", arise from misunderstanding. The material used for my study 

 of the nerve components was not the ammocoetes of Lampetra, as 

 Tretjakoff states, but the ammocoetes of Petromyzon dorsatus (1905, 

 p. 149, 197). He states further that, that study was made upon sections 

 stained with haematoxylin ; in fact I stated that haematoxylin sections 

 were unfit for that study and explained fully the combination stain 

 used (p. 150). The author attributes the differences between his de- 

 scription of nerve roots and mine to my errors of observation, since 

 he does not think they can be due to differences between species. 

 Such differences, however, do exist. I described important differences 

 between the two species studied by me (1905, p. 197, 169, 192 and 

 elsewhere) and it is quite possible that the discrepancies between 

 Tretjakoff's description and mine are due to differences between 

 species as well as to errors and oversights in Tretjakoff's observations. 



P. 670 — 671. The author has not understood my description of 

 the fasciculus communis root of the N. facialis, nor has he appreciated 

 the fundamental difference between sensory fibers which supply the 

 skin and lateral line sense organs in the skin, and those which supply 

 mucosa of the pharynx. Of this more beyond. 



P. 674. The author quotes me as saying that a part of the sen- 

 sory fibers of the trigeminus go into the medial part of the oculo- 

 motor nucleus and says that he can confirm this. The fibers in 

 question go into the "tuberculum acusticum". 



P. 676. The author criticizes Schaper and myself for recognizing 

 Purkinje cells in the cerebellum. In fact, I criticized Schaper for 

 calhng the cells in the cerebellum Purkinje cells (1902, p. 59 — 60) 



