MICROBIAL DISEASES OF MAN AND ANIMALS. 599 



The organism gains entrance through the respiratory mucosa and as 

 a matter of fact appears to be a common inhabitant of these regions. 

 However the organism may reach the lung (the lobar distribution sug- 

 gests sowing by the blood stream), it is certainly frequent to find positive 

 blood cultures during the disease a fact which accounts for the develop- 

 ment of such complications as meningitis, endocarditis, etc. The. 

 toxaemia probably arises from lysis of the organisms and it has been 

 shown that the autolysis of cultures in salt solution gives rise to a soluble 

 toxic portion and an insoluble non-toxic portion. 



Immunity to Pneumococcus infections can be shown to exist after an 

 attack but only for a short time. 



Pneumococci may be considered as inhabiting the mucous membranes 

 of the respiratory tract in the majority of people and acquire virulence 

 only under some special circumstances lowering the general vitality. 

 In pneumonia and some kinds of bronchitis as above mentioned it 

 should be remembered that sputum and mouth spray may contain large 

 numbers of virulent organisms. 



Specific therapeutic agents such as antipneumococcic sera, vaccines of 

 dead cultures and autolysates, as well as leucocyte extracts, have been 

 tried and all with some promising results. Not one of these methods, 

 however, has been sufficiently widely applied with success enough to 

 warrant general adoption. 



The prophylaxis of Pneumococcus infections lies in general hygienic 

 measures, in the destruction of sputa and avoidance of possible infection 

 by mouth spray, etc. 



ANTHRAX.* 

 Bacterium anthracis* 



Also called splenic fever or charbon; and in man, wool-sorter's disease 

 or malignant pustule. 



The disease has been known for centuries. It is thought that it was 

 one of the plagues of Egypt, mentioned as a murrain on beasts, and boils 

 and blains on man and beast. The first accurate characterization of 

 the disease was made by Chabert about 1800. Pollender in 1849 and 

 Rayer and Davaine in 1850 reported that they had seen "filiform bodies" 

 in the blood of animals which had died of anthrax, and in 1860 Davaine 



* Prepared by F. C. Harrison. 



