Literary Notices. ci 



2. The normal cerebral venous pressure in the dog is equivalent 

 to ioo — 1 20 mm. water. 



3. The pressure in the superior longitudinal sinus with the flow 

 of blood obstructed rises to double or more the normal cerebral ven- 

 ous pressure. 



4. The air index in the measuring apparatus exhibits perfectly the 

 cardiac and respiratory undulations of the intra-cranial pressure. 



5. The water manometer in connection with the venous cavity in 

 the occipital protuberance, or with the longitudinal sinus, exhibits the 

 cardiac pulsations and large respiratory undulations. 



6. Salt solution (0.6 per cent.) can be slowly driven into the sub- 

 dural space at the rate of about 1 c.c. a minute without raising the 

 intra-cranial pressure or producing any physiological effects. As 

 much as 20 c.c. has thus been driven in during one experiment. 



7. Salt solution can be driven through from the parietal hole to a 

 hole in the lumbar region of the spinal column. The whole of the 

 subdural space can thus be syringed through. 



8. Salt solution cannot be driven from a hole in the lumbar re- 

 gion out of a hole in the parietal region. The brain floats up and 

 closes the parietal hole as a valve. 



9. Salt solution, if driven in quickly with a higher pressure, pro- 

 duces a momentary rise of intra-cranial pressure and momentary 

 physiological effects. These disappear very rapidly as the solution is 

 absorbed. 



10. On introducing 0.5 c.c. of salt solution within a bag in the 

 sub-dural space of a cat, no rise of intra-cranial pressure occurs, and 

 no physiological effects are produced. 



11. The introduction of more than 0.5 c.c. produces a lasting 

 rise of intra-cranial pressure and physiological effects. These are: 

 (1) slowing to stopping of respiration; (2) rise of blood pressure and 

 slowing of the heart; (3) dilatation, or extreme constriction, of the 

 pupil, and some times nystagmus. 



12. The cat may become habituated to the smaller degrees of 

 heightened intra-cranial pressure, and the physiological effects pass off. 



13. Greater amounts than 1 c.c. cause an enormous and main- 

 tained rise of arterial pressure, with acceleration of the heart, inspira- 

 tory gasps at long intervals, followed by fall of arterial pressure and 

 death. 



14. 0.5 c.c. is the largest amount of displacement which can be 

 perfectly compensated for in the cat, i.e., this is the reduction of the 



