DOMESTIC ANIMALS. 175 



horses with, sensitive skins. The common fly too is 

 very annoying to many animals in the latter part of the 

 summer. The annoyance and irritation caused by the 

 parasites tend to keep many horses poor in flesh, re- 

 duce the amount of milk yeilded by cows, and when 

 they are exceedingly numerous, often act as predis- 

 posing causes of other and more serious disorders. We 

 shall not in this place notice the gad, bot, or grub-fly, 

 but describe each under the heading of the disease it 

 causes, 



Treatment. Keep stable and other buildings where 

 animals are housed as dark as possible; use screens to 

 prevent the entrance of flies when the windows and 

 doors are open. When at work where these pests are 

 especially annoying, fly nets may be advantageously 

 used. Twigs or the small branches of trees attached 

 to parts of the harness are very useful as preventives. 

 The application of a solution of walnut tree leaves once 

 a week is said to be an* excellent preventive. The 

 leaves should be boiled for a few minutes; but the ani- 

 mals may be simply rubbed with the leaves themselves. 



FLEAS. 



This order of parasite is very annoying to many ani- 

 mals. Drawings of the heads of some of them are shown 

 in Figs. 64, 65, 66 and 67. 



Fig. 64. Head of man flea. Fig, (55. Head of dog flea, 



