cii Journal of Comparative Neurology. 



cranial capacity which can be made up for by escape of cerebro-spinal 

 fluid. 



15. The brain of the cat of ordinary size, measured up to the 

 level of the calamus scriptorius, equals in volume 26C.C. 



16. The amount of compensation is reduced to nothing on re- 

 peating the experiment a second time, and the effects which follow 

 the introduction of the same quantity of salt solution into the bag are 

 much more marked. 



17. In the dog of the fox-terrier size the amount of compensation 

 is 1.5 c.c. 



18. The brain of the ordinary fox-terrier, on an average, equals 

 64 c.c. in volume. 



19. The introduction of more than 1.5 c.c in the dog produces 

 a lasting rise of intra-cranial pressure and physiological effects. 

 These are the same as in the cat, except that there is no rise of blood 

 pressure. 



20. On cutting both vagi in the dog, the rise of blood pressure 

 occurs as in the cat, and may reach enormous amounts. 



2i. The compensation is reduced to nothing in the dog on re- 

 peating the experiment a second time and the effects are much more 

 severe. 



22. The physiological effects can be immediately removed by 

 emptying the bag, and the pressure in the intra-cranial cavity recovers 

 its old standard. 



23. If the displacement caused by the bag is large, and main- 

 tained for a considerable time, there may be no relief and no expan- 

 sion of the brain on emptying the bag. 



24. Trephine holes made in various parts of the cranium and 

 vertebral column afford no relief to the effects produced by the bag. 



25. No fluid is to be found within the subdural space after the 

 "bag experiment." The surface of the brain and the cavity of the 

 skull are quite dry. 



26. After the " bag experiment," salt solution can no longer be 

 absorbed, and can no longer be driven through to a hole in the lum- 

 bar region, but acts in the same way and produces the same effects as 

 the bag. 



27. Marked physiological effects occur in the cat when the intra- 

 cranial pressure is raised 10 mm. Hg above the normal. The meas- 

 urement is taken over the medulla oblongata. 



28. The venous pressure in the cavity of the occipital protuber- 

 ance falls to zero when the " bag " is distended over the parietal re- 





