Anaphylaxis in Lower Monkeys. 



61 



On April 22 this animal was again titrated against horse serum, 

 and distinctly positive ring tests were obtained against horse 

 serum dilutions of 1-5, 1-10, extremely faint and hardly noticeable 

 in 1-20 . 



May 5, again titrated with practically the same result, except 

 that reactions were somewhat weaker than on April 22. Skin 

 reaction done on this day shows a doubtful reaction which, how- 

 ever, might have been regarded as a faintly positive one. On this 

 day, 4 c.c. horse serum injected intravenously was followed imme- 

 diately by shivering, watering of the eyes, and monkey continu- 

 ously rubs nose and eyes as though they itched. No other 

 symptoms. 



In these monkeys, in a considerable number of titrations, the 

 monkey serum titrated against anti-horse rabbit serum showed 

 reactions which seemed positive again and again for sometimes 

 as long as two weeks after the last injection, with appreciable 

 diminution. This made us suspicious of the specificity of the 

 reactions, and we obtained, through the courtesy of Dr. Cecil, 

 specimens of the serum of 7 normal monkeys which we titrated 

 against 4 different specimens of ahtihorse serum from 4 different 

 rabbits, and found that in almost all cases precipitates were 

 given by antihorse serum against the normal monkey sera in 

 dilutions as high as 1-10. These monkeys all belonged to the 

 Macacus variety, and it was obvious that our apparent antigen 

 persistence was due to a normal reaction between anti horse 

 serum and normal monkey serum. Similar titrations done at 

 the same time against five different normal rabbit sera give only 

 one ± reaction between normal rabbit "5" and normal monkey 

 "5." All other reactions were entirely negative. 



Although we cannot explain this, it seemed possible that we 

 might have been dealing with a peculiarity due to unsuspected 

 antigenic relationship between monkey serum and horse serum, 

 a fact which might also possibly explain the failure of the monkeys 

 to react to the horse antigen. 



In consequence we shifted further experiments to egg white, 

 instead of horse serum. 



Three monkeys were systematically treated with egg white 

 made up in ^concentrations of 1-5, by slaking egg white in salt 



