ii8 Journal of Comparative Neurology. 



the opposite, the intermediate tracts receive one fibre, the short 

 tracts eight fibres (two ascending and two descending ones on 

 each side). 



According to Birge, the brachial enlargement of the spinal 

 cord receives about 4000 root-fibres, the dorsal "region 1500, 

 and the lumbar enlargement about 4500, " making altogether 

 10000 root-fibres. Gaule counted the fibres of five sections, 

 and compared the actual number with the number obtained on 

 ground of his hypothesis. For the first section (from the 

 upper end of the cervical cord) he makes the following calcula- 

 tion: 



1 . Fibres of the long tracts, 2 for each of the root- 



fibres entering the spinal cord. io,O0O x 2 20,000 



2. Fibres of the intermediate tracts : none ; as they 



don't reach this segment. 



3. Fibres of the short tracts. 4 to each fibre of the 



half of the brachial enlargement 11^ x 4 8,000 



Fibres of one half of the section 28,000 



Fibres of the whole section 56,000 



The results of the hypothesis and of the actual number 

 obtained in the 5 sections compare very favorably: 



Section I. Hypothesis 56000 actual number 56674 



" 11. " 74000 " " 74699 



" III. •' 45500 " " 41825 



" IV. " 60500 " " 61058 



" V. " 18000 " " 16313 



Conclusive as this proof of the hypothesis seems to be, 



there is no doubt that it has to be accepted with due reserve for 



reasons too numerous and too obvious to be mentioned here. I 



put this abstract before the reader, because this instance is a 



fair example of the speculative character of Gaule's work. 



Dr. Wlassak, Gaule's assistant, has so far published an ana- 

 tomy of the cerebellum of the frog and is now preparing a num- 

 ber of interesting studies on other parts of the amphibian brain. 

 In this short review I have not been able to do full justice to 

 any one of the Zurich scholars; but if I have succeeded in induc- 

 ing some of my readers to take up a careful study of the works 

 mentioned, I feel confident that they will agree with me in call- 

 ing Zurich a remarkably productive neurological center. 



