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 
yi) hands (Fig. 83). 
This organism is not only 
y capable of cultivation, but rabbits 
and dogs can be inoculated with 
Fig. 83.—Malaria bacillus it, So as to produce marsh fever 
aceon 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 Schezophytum, 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. 
