484 University of California Puhlications in Zoology [Vol. 20 



in horses infected with dourine. Normal horses showed a reaction 

 persisting from 20 to 24 hours. The authors considered the reactions 

 in the infected animals to be similar to those obtained in positive 

 mallein reactions. Nusshag (1921) described inconclusive results 

 obtained in dourine by the intradermal injection of .25 ce. of antigen 

 prepared from trypanosomes. A faintly reddish papule appeared 

 in 5 hours, reached its height in 18 hours, and disappeared within 

 24 hours. In the light of the tuberculin and typhoidin reactions, 

 these results could scarcely be considered positive, but rather as a 

 non-specific protein reaction. Force and Stevens (1917) consider 

 specific only those intradermal reactions which reach their height 

 at 48 hours and persist for at least 72 hours. The work of De Gaspari 

 (1921) on dourine has been inaccessible. The reactions obtained by 

 the intradermal injection of the alkaline extracts of L. tropica and 

 L. infantum in immune rabbits are %vithout doubt comparable to those 

 obtained with tuberculin, typhoidin, and vaccine lymph. 



It is of importance to note that rabbits immunized to one species 

 of Leishmania are sensitive to the protein of both species, L. tropica 

 producing the most pronounced reaction even in animals immunized 

 to L. infantum. Hamman and Wolman (1912) have found that both 

 human and bovine Old Tuberculin produced approximately the same 

 sized papule in 127 out of 150 cases of tuberculosis tested. Meyer 

 and Christiansen (1917) stated that some typhoid immune rabbits 

 show non-specific reactions with paratyphoid and B. coli extracts 

 which can be considered as group reactions. 



These group reactions do not impair the diagnostic value of the 

 skin reaction as a means of detecting hypersensitiveness to protozoan 

 proteins. At the present time insufficient work has been done to 

 determine the value of these tests in man or in animals infected with 

 protozoa. It is hoped, however, that the results of this investigation 

 may be made the basis for similar tests on cases or convalescents from 

 leishmaniosis. 



