CONSTITUTIONAL DISEASES. 369 



Some dogs possess immunity from tins malady, and rarely 

 does the subject have the disease a second time. 



It is possible, perhaps, that distemper can be conveyed 

 throiio-h the air, but it is usually by contact with either an 

 affected animal or with the poison (virus), which may be 

 adherent to some inanimate body or the body of some dog 

 that is not himself perhaps susceptible. 



Anything that tends to lessen an animal's resisting 

 power, as a sudden alteration in the environment, like a 

 change of weather or of feeding, exposure to wet and 

 cold, exhaustion, a long journey, the exciting and un- 

 natural conditions of shows generally (see page 393), with 

 tlie crowding together of large numbers of dogs that 

 have lived under different conditions, etc. — all such favor 

 the spread of the disease. 



Prophylaxis, or prevention. — Much more can be done 

 to ward off distemper than to cure it, and a consideration 

 of the predisposing causes v^dll suggest means of pre- 

 vention. 



It will be noticed that distemper is most rife in Amer- 

 ica during and after the fall shows in September and Oc- 

 tober. At this period many puppies are getting their sec- 

 ond teeth, their constitutions are still very immature, and 

 the nervous system — the great regulator of all vital pro- 

 cesses — very unstable. It can not be doubted that shows 

 favor the production of distemper, and must do so even 

 when all precautions are taken ; for the germs of the dis- 

 ease are so widely spread, that it would seem that all that 

 is required for its propagation is a young animal with a 

 somewhat temporarily lowered vitality. 



Hence it follows that puppies should be kept at home, 



