94 IMMUNO-CATALYSIS 



an equal volume of tyrode solution and introduced into the peritoneal 

 cavity of rabbit by means of regular surgical technic. This rabbit later 

 developed symptoms of nagana and trypanosomes were demonstrated 

 in its blood. Two drops of ear blood from this animal were inoculated 

 into a rat which contracted the disease and died after 8 days. Fifty- 

 three days after the original inoculation, this rabbit was found dead. 

 This particular experiment shows that at least a few trypanosomes 

 were present in the tissues or organs of the forest deer mouse, an animal 

 which had been relatively immune on the basis of negative microscopic 

 examination of its blood, as well as on the basis of the noninfectivity 

 of its blood to rats. 



In another set of studies Packchanian and Tom (1943) reported the 

 presence of agglutinins for Leytosfira icterohaemorrhagiae in the 

 circulating blood of patients for periods from one year to at least 20 

 years and seven months after recovery from Weil's disease. It is inter- 

 esting that in all cases during the periods indicated there has been a de- 

 cline in the agglutinin titer. However, the sera were never free from ag- 

 glutinins of significant titer. Following up these findings Packchanian 

 and Sonnier (1948) found that tests for agglutinins in the serum 

 samples of 18 rats (R. norvegicus') were negative and no Leptos'pira 

 were found in the kidneys of these rats. However, the serum samples 

 of a wild rat, whose kidneys were positive for motile Le'ptos'pira, gave 

 agglutination reaction with Type I Leptospira icterohaemorrhagiae in 

 dilutions up to 1 : 30,000 and the serum sample from an infected mouse, 

 whose kidneys also were positive for Leptospira, gave an agglutination 

 reaction in dilutions up to 1 : 10,000. 



These investigators have shown that less virulent strains of Lepto- 

 spira may fail to produce death in guinea pigs, but may produce anti- 

 bodies, such as agglutinins and lysins as a result of subclinical infection. 



Burnet, et at. interpret the above claimed long-lasting immunity in 

 the following manner. The fractions of the serum globulin which are 

 concerned in immunological reactions are synthesized by cellular pro- 

 teinase units. These liberate partial replicas of themselves. These 

 proteinases, by virtue of their enzymatic function, come into contact 

 with any foreign antigens taken into the cell, are lastingly modified by 

 this contact. The modification of the proteinase unit which is produced 

 by contact with the antigen is not to be regarded as resulting from a 

 synthesis of a new unit in spatial contact with antigen, but rather as a 



