311 



The horse has a stomacli whicli is decidedly small (8.15 L.) and 

 a dorsal motor X mieleiis which is equally small ^comp. fig. 3), the 

 ruminantia have an enormons stomach (cow =t 200 L.), which in 

 some compartments is very rich in musculature and glands. In 

 accordance we find a very large dorsal X nucleus in the cow 

 (see fig. 4). 



Also the pig is well provided in this respect if we consider the 

 small size of its body (stomach 7.8 L.) and equally the dog. In the 

 latter the stomach varies considerably according to the race, but as 

 a rule is well developed (according to Mentzlaff 8.26 — 29.31 % of 

 the body-weight). Among our ruminant animals we find the difference 

 that a ventricular compartment, which in the cow is very muscular 

 is poorly developed in the goat and the sheep. Perhaps this explains 

 the fact why in the latter the dorsal X acquires only its greatest 

 size in its frontal third part, whilst in the cow the nucleus already 

 acquires its greatest dimensions in the middle and keeps this maxi- 

 mum over a much longer distance than the sheep and the goat (see fig 2j. 



Now comparing the shape of the caudal part of the floor of the 

 fossa rhomboidea with the above mentioned differences in the size 

 and form of the dorsal motor nucleus, we understand why in those 

 animals where this nucleus is more considerably developed and 

 contains a great many motor cells the floor protrudes in the ventricle. 



That this is not so in the dog may depend on the fact that this 

 nucleus is only small directly in front of the calamus, and only 

 acquires its greatest size in the frontal third part. 



Finally I make use of this occasion to rectify a slip of the pen 

 that has occurred in C. Ü. Ariëns Kappers's VII'^ communication 

 on Neurobiotaxis, on p. 97. Dealing with the dorsal motor nucleus 

 of the horse the author says: "Nur heiiR P/erd fand Vermeulen ihn 

 erheblich grosser, was er mit dem grossen Magen dieses Tieres in 

 Verbindung bringt". This must be of course "nur beim Rinde". 



Anatomy. — "On the relation between the quantity of white and 

 grey substance in the central nervous system." By Dr. A. J. 

 HovY, Utrecht. (Communicated by Prof L. Bolk). 



The relation between white and grey substance in the central 

 nervous system has frequently puzzled the mind of neurologists. So 

 authors (Chiari, Heschl, Jelgersma and others) have alluded to it 

 when dealing with the gyrated surface of the brain. 



The quantitative relation has however rarely been measured 

 with any amount of exactness. The greatest obscurity still exists as 



