ABSORPTION FROM THE VENTRICLES Z\d 



bellomedullaris. The kittens received Ij cc, the rabbits 5 cc. 

 of lampblack suspension. The immediate mortality from this 

 procedure was rather high and due, as far as could be ascertained, 

 either to injury to the rhombencephalon or to respiratory failure 

 from the sudden increase in pressure on the medulla. 



The animals surviving the injection recovered from either and 

 appeared normal in all respects. The day following the injection 

 nothing unusual could be observed. The first signs of a develop- 

 ing hydrocephalus could be made out on the second, more often 

 on the third or fourth day. Gradually the enlargement of the 

 cranial vault became noticeable and a diastasis of the cranial 

 sutures could be made out. The animals' behavior changed 

 somewhat. Slight ataxia was nearly always noted and tremors 

 were observed in several instances. The injected animals 

 appeared to be less active than the normal controls. 



Several deaths occurred during the first ten days, some from 

 intercurrent pneumonias, others from undetermined causes. On 

 the tenth day eight kittens and four rabbits with well-developed 

 hydrocephalus were alive and in good condition. These v/ere 

 used for the injection of the ventricles. 



The animals were divided into two groups, one group receiving 

 a 2 per cent solution of equal parts of potassium ferrocyanide 

 and iron ammonium citrate, the other group a i\- per cent solution 

 of trypan blue. The experimental procedure was as follows: 

 The skin of the head was shaved and cleansed, a sharp, 26 — 

 gauge needle was inserted through the skin and bone into one of 

 the lateral ventricles, and two drops of fluid were permitted to 

 escape, whereupon an antitoxin syringe was connected with the 

 needle and an equal quantity of potassium ferrocyanide and iron 

 ammonium citrate or trypan blue was injected. The needle 

 was removed and the animal released. The animals receiving 

 potassium ferrocyanide and iron ammonium citrate were killed 

 at intervals varying from thirty minutes to two hours, those 

 receiving trypan blue at intervals from eight to twenty-four 

 hours. The brains injected with potassium ferrocyanide and 

 iron ammonium citrate were fixed in 10 per cent formalin plus 

 1 per cent hydrochloric acid. The acid precipitated the ferro- 



