The Fixation of Arsenic by the Brain. 



325 



with 0-05 grm. of neosalvarsan. They were killed 12, 36, and 60 hours after 

 the last dose and transfused as before. 



The following results were obtained : — 





Babbit A, 

 12 hrs. 



Babbit B, 

 36 hrs. 



Babbit C, 

 60 hrs. 





Gra 



o-oooi 



-0005 

 0003 



mmes of neosalvar 

 -00004 

 -00075 



-oooi 



san. 







-00075 

 



Experiment 9. — Repetition of Experiment 8, but all the animals killed 

 24 hours after the last dose. 





Babbit A. 



Babbit B. 



Babbit C. 



Brain (ca. 10 grm.) 



Blood (25 c.c.) 



Gra 







-00012 

 



mmes of neosalvar 

 



' o -oooi 

 o -oooi 



san. 







0005 

 



From these experiments it appears that no definite penetration of the 

 ■drug into the brain can be obtained by a repetition of the injections, although 

 in one case a small quantity was observed 12 hours after the last dose. 



Similar results were obtained with Prof. Ehrlich's new copper-salvarsan 

 combination (k s ). 



Experiment 10. — Technique as in Experiment 8. The dose of hz was 

 O"02 grm. and the animals were killed 24 hours after the last injection. 



i 



Babbit A. 



Babbit B. 



Brain (ca. 10 grm.) 



Liver (10 grm.) 



Blood (25 c.c.) 



Grammes of 

 



-00002 

 



neosalvarsan. 

 



-0005 







Conclusions. 



1. After intravenous injections of salvarsan and neosalvarsan in man and 

 •animals no arsenic can be found in the brain. 



2. This phenomenon is not due to a lack of affinity between the brain and 

 the drugs, but to an inability on the part of the drugs to penetrate into the 

 substance of the brain. 



