Meyer, Neurologists and Neurological Laboratories. 1 1 7 



doubt that we are going to obtain many valuable contributions 

 from this author. 



Prof. I. Gaule' has written several interesting neurological 

 papers. His work is, of course, largely dealing with physiology 

 but has so many original features that I wish to mention one paper 

 on the numerical relations of the medullated fibres of the spinal 

 cord of the frog. Gaule compares the number of the fibres of the 

 cross-section with the corresponding number of the entering 

 perpherial nerve-fibres. He starts from the following supposi- 

 tions: 



1. Every fibre of the white substance is in functional 

 coordination with the central ends of the root-fibres. 



2. The fibres of the white substance form connections 

 among the central ends of the root-fibres themselves and with 

 the brain. 



3. The white fibres may be divided into the following 

 groups: 



a. tracts which go beyond the spinal cord into the oblon- 

 gata and other parts of the brain, — the long tracts; 



b. connections within the spinal cord among its various 

 segments — intermediate tracts; 



c. connections of all the single elements within the same 

 area — short tracts, 



4. The central end of every root-fibre corresponds to a 

 certain number of fibres of the white substance, the number be- 

 ing constant for every one. 



5. The central ends of the root-fibres and consequently 

 the starting-points of the corresponding fibres are not far from 

 the entrance of the roots into the spinal cord. 



6. The length of the fibres of the white substance depends 

 on their function, i. e. , on the distance of the segments united. 



7. The central end of every root-fibre contributes two fi- 

 bres for the long tracts, the one for the same side, the other for 



^Gaule, J. Zahl und Vertheilung der markhaltigen Fasern im Froschriick- 

 enmark, Mit 9 Tafeln. Abhandlg. d. mathemat. phys. Klasse der kgl. sachs. 

 Ges. Wiss. XV. 9. p. 739. 1889 and Edinger Jahresbericht f. d. Jahr 1890; p. 

 31-33- 



