428 



Drs. C. Shearer and H. W. Crowe. 



the following experiments. The trypan blue test bore out the results 

 obtained with the warm stage. The leucocytes do not take up the stain as 

 long as the spinal fluid is simply cloudy and turbid and no traces of pus 

 present. This test, moreover, would seem to show that human leucocytes 

 can remain alive for 2-3 days in the spinal fluid, when this is allowed to 

 stand at room temperature under sterile conditions. 



In the following experiments we made use of spinal fluid which we had 

 every reason to believe, in view of the above tests, contained living leucocytes. 

 In no instance did we use fluid showing the presence of pus cells. The results 

 of the experiments themselves preclude, moreover, the possibility that the 

 majority of the leucocytes were dead. 



Experiment 2. 



In this, as. in the former experiment, leucocytic deposit of fresh " Sloan " 

 spinal fluid, containing this time practically no free germs, but many 

 within the leucocytes, was removed and washed. Part only was washed in 

 1 per cent, glucose. The remainder was washed in 085 per cent. NaCl. 

 The washings in both instances were repeated 16 times, to make certain, as 

 far as possible, that no free germs should remain. 



Microscopic examination of the deposit after washing in glucose showed a 

 slight disorganisation of the leucocytes, while those washed in saline showed 

 no change. The normal saline, while not affecting the leucocytes, presumably 

 exerted a toxic action on the free germs or those attached to the exterior 

 surface of the leucocytes. Those within were protected from its action. 



Expt. 2. — Fresh " Sloan " spinal fluid, containing no free cocci, but large numbers 

 within the leucocytes, was centrifuged lightly to bring down leucocytes. 



Treatment. 



Growth, 24 hours. 



(1) Leucocytic deposit of spinal fluid washed 16 times in 



1 per cent, sterile glucose, and planted out 



(2) Leucocytic deposit of spinal fluid washed 16 times in 



sterile 0'85 per cent. NaCl, and planted out 



Good. 



Good, but delayed : at end of 

 48 hours, same as (1). 



In this experiment (1) we got a rapid and immediate growth covering 

 nearly the whole of the plate at the end of 24 hours. In (2) the growth 

 only attains to the amount of that of (1) at the end of 48 hours. In both 

 (1) and (2) practically all free cocci have been eliminated by the repeated 

 washings. Those remaining over or attached to the surface of the leucocytes 

 in (2) have been killed or injured by the toxic effect of the saline. Those 



