318 MALTA FEVER, ETC. 



The disease is contagious, but the method of infection is 

 not known. It is possible to produce the disease experi- 

 mentally in animals by inoculating them with the blood of 

 relapsing fever patients. It has been suggested that insects 

 play an important role in the transmission of the disease, 

 but such a method of infection has not been demonstrated. 

 Intra-uterine transmission has been observed. The inability 

 to cultivate this organism has interfered with all attempts to 

 learn something of the nature of the disease ; the method of 



FIG. 142. 



Spirillum Obermeieri in blood of man. X 1000. (Fraenkel and Pfeiffer.) 



infection ; whether the symptoms are due to the germ or to a 

 toxaemia ; finally what dispositien is made of the germ when 

 the disease has run its course. The germ may be disposed 

 of by the phagocytes or by an insusceptibility of the blood, 

 due to its saturation with some substance which is fatal to the 

 spirochsete. 



Whooping-cough. 



Various observers have from time to time found a number 

 of organisms in the sputum of children suffering from whoop- 



