452 Pathogenesis of Undulant Fever 



metastases may lead to suppurative processes. Fatal septicemic infections are 

 exceptionally rare. 



Finally, it is not out of place to reflect briefly on the significance of the intra- 

 cytoplasmic parasitism of Brucella. If this phenomenon can be proved to be as 

 common as is indicated in the growing chick and in the few observations here 

 recorded, the concepts of the immunity mechanism, which places the entire 

 weight on the antibodies, may require a fundamental revision. In fact, the 

 well-known realization that it is impossible to create any noteworthy degree 

 of acquired resistance with killed vaccines might possibly receive proper ex- 

 planation. Just as in tuberculosis, the degree of protection afforded is pro- 

 portional to the extent of the primary lesion or lesions. Only a true infection 

 can produce extensive lesions in which a great many cells of the reticulo- 

 endothelial system participate. Furthermore, these cellular elements may have 

 had intimate contact with the Brucella organism. But what is more important 

 is the antigenic structure. There is every reason to suspect that the antigens, 

 which develop as a result of the intracellular parasitism, may in some respect 

 be different from those generated in artificial media. A true infection will, 

 in contrast with the injection of culture antigen, produce immunity. More- 

 over, it is equally probable that the susceptible mesenchyme cells and their 

 descendants may be rendered immune only through infection or temporary 

 intracytoplasmic parasitism and not through mere exposure to soluble an- 

 tigens. There is no doubt that the viability and in particular the latency— one 

 of the most important manifestations of a Brucella infection in cattle, goats, 

 and hogs— is intimately connected with the intracellular development cycles. 

 Viewed from these angles the Brucella problem, so hopelessly bewildering, 

 deserves renewed critical inquiries and experiments. 



Summary 



(i) The pathological and bacteriological findings made on an acute malig- 

 nant infection due to Br. suis No. 80 in a laboratory-animal caretaker is re- 

 ported. The circumstances surrounding the infection strongly indicate the 

 ingestion of a very heavy suspension of the specific bacteria. According to the 

 positive allergic skin reaction and the strong opsono-cytophagic response 

 (index 6:88) the patient had been considered immune to brucellosis. 



(2) The metastatic lesions in the kidneys were not embolic but due to the 

 elimination of brucellas through the glomerulus. The bacteria developed in 

 the epithelium of Bowman's capsule and the proximal end of the convoluted 

 tubules. The significance of the intracytoplasmic parasitism is discussed. 



(3) The genesis of Brucella infections is critically analyzed and suggestions 

 for further studies are presented. 



REFERENCES 



i.Fabyan, M.: Jl. Med. Resrch. 28:81, 1913. 



8.Meyer,K.F., and Zobell, C. E.: Jl. Infect. Diseases 5 1:72, 1932. 



3. Sharp, W. B.: Archs. Pathol. 18:72, 1934. 



