DIAGNOSIS OF AFRICAN TICK FEVER. 235 



that the blood of the animal when taken at these periods contains too few 

 spirochsetae to render the test satisfactory or conclusive, and this may 

 occur although the animal was previously inoculated with a large amount 

 of blood richly infected with spirochsetfe. In some instances the spiro- 

 chsetse in the blood may appear to be ideal for the performance of the 

 test, the parasites being numerous, active and not agglutinated, yet when 

 they are added to a normal serum they may undergo spontaneous aggluti- 

 nation as marked as if an immune serum had been employed. Again, 

 in some instances in the same period of time that they become aggluti- 

 nated and clumped in the immune serum, they may undergo the same 

 apparent process in their own serum, without the addition of that of 

 the blood to be tested. The parasites at other times may appear to be 

 very numerous in the blood at the time of the examination and in the 

 few minutes required to bleed the animal they may apparently all 

 disappear before anything is added to the blood. These phenomena may 

 be understood at least partially when one considers that in the infected 

 animal the agglutinins and spirolysins are being developed gradually with 

 the development and increase in number of the spirochseta?, and hence 

 in animals which show a very rich infection with spirochostse, agglutinins 

 and spirolysins are already present to a greater or less extent. Sometimes 

 the withdrawal of the blood seems to be all that is necessary to stimulate 

 the complements and antibodies to action and in other instances the 

 additional amount of these corresponding substances, either present in 

 the normal or immune serum, may be necessary to bring about the 

 phenomenon of agglutination or of bacteriolysis. Sometimes it will be 

 necessary to take the blood from several animals before one is found in 

 which a satisfactory condition of the spirochffitse exists for the perform- 

 ance of the agglutinative or bacteriolytic test. Indeed, on some occasions 

 it has taken me three or four days before satisfactory conditions for even 

 the proper performance of these tests could be obtained. Obviously, the 

 employment of the spirolytic test in the abdominal cavity of an animal 

 presented even greater difficulties. It therefore seemed highly desirable 

 that some other means be found that would serve as an aid in the diagnosis 

 of the disease and in the differentiation of its different varieties, and I 

 determined to see if the precipitin reaction might be employed for this 

 purpose. Evidently if this reaction could be shown to be satisfactory 

 for this purpose the diagnosis of this group of diseases would be much 

 simplified and at once placed upon a practical basis. 



As is well known, Kraus - in 1907 first showed the existence of specific pre- 

 cipitins for the albuminous bodies found in bacterial cultures. Later it was 

 demonstrated that the reaction might be employed for the differentiation from 

 one another of the vibrios of Finkler and Prior, Nasik, Denecke, and of Metch- 

 nikoff, and also for differentiating colon from paracolon bacilli. Wladimiroff " 



-Wien. him. Wchnsch. (1897), 10, 736. 



M Kolle und Wassermami Handbuch d. pathogen Mikrorgan. (1904), 4, 1055. 



