THE MICROBES OF HUMAN DISEASES. 183 



produced in artificial cultures. It is not found in the 

 healthy parts of Lombardy. In the strata of air 

 which float above malarious ground in summer, this 

 microbe is so common that it is found in abundance 



in the sweat of the forehead and 



hands (Fig. 83). 



This organism is not only 



capable of cultivation, but rabbits 



and dogs can be inoculated with 

 bacillus ^ so to produce marsh fever 



in them.* The lesions which 

 are observed in an autopsy are the same as those in 

 man, showing that the site preferred by the microbe is 

 the spleen and the marrow of the bones. 



The fact that the bacillus ' and its spores are suc- 

 cessively found in the blood explains the intermittent 

 type of the disease, tertian, quartan, etc., according to 

 the variety of marsh fever. According to its variety, 

 and perhaps to the species of Schizophytum, the com- 

 plete evolution of the plant sometimes demands 48, 

 sometimes 72 hours, and the access of fever always 

 corresponds with the period of greatest activity in 

 the bacillus that which precedes the emission of 

 spores. 



Two military surgeons, Laveran and Richard, 



* It is generally believed in France that animals, and especially 

 herbivora, cannot contract intermittent fever. This opinion is erro- 

 neous. It is known that in Italy cattle contract this fever when they 

 are not acclimatized to marshy districts, and that they are cured by 

 sulphate of quinine. 



