200 SOME MINUTE ANIMAL PARASITES 



study of the blood of such patients that the cure for 

 the disease will be found. 



Though L. infantum chiefly affects children, it is 

 not confined to them, for it has been recorded from 

 people aged 17 at Tripoli, 18 at Stromboli, 19 at 

 Rome, and a case at the age of 38 was noted in 

 Calabria. These are somewhat exceptional, but they 

 serve to link the range of the Mediterranean with 

 the Indian form, though, unlike the Indian parasite, 

 it is easy to produce multiplication of L. infantum 

 on artificial substances, or cultures, and it can 

 readily be reproduced in dogs and monkeys. It is 

 almost impossible to reproduce the Indian disease in 

 animals, and very few cases of success have been 

 recorded. 



During the investigations of this infantile Kala- 

 azar, two startling discoveries were made. In the 

 first case a large number of dogs was found har- 

 bouring a parasite identical with L. infantum in their 

 blood ; also they were short-lived when the parasite 

 was present. In the second case it was found that 

 children living in jcontact with infected dogs also had 

 Kala-azar. This at once suggested that if the 

 parasite of dog and child were identical, some insect 

 that frequents both man and dog was responsible for 

 the transference of the disease to the human host. 

 Much work was done and by various means. An 

 investigation of the dog parasite was made, and in 

 order to study the disease as far as possible without 

 other complications intervening, specially bred dogs 

 free from the disease were artificially infected. The 

 malady took one of two courses, In young animals 



