STATE HYGIENE 559 



danger which would result in hot weather from closing the 

 troughs. 



This is a very important point in legislating against the 

 disease, and unless supported by the weight of Mr. Hunt- 

 ing's authority and observation, we should certainly have 

 taken the other view, for the organism of the disease can 

 remain virulent in water for many days. It is quite 

 possible the comparative immunity enjoyed by horses 

 watering at a public trough, is due to the fact that a man 

 driving a horse with a nasal discharge, or one he believes to 

 be glandered, does not water it at a public trough to avoid 

 the risk of detection. 



This observation might suggest a better knowledge of 

 glanders on the part of carmen and drivers than they 

 actually possess. They know it is a disease associated 

 with a discharge from the nose, and if a case has occurred 

 previously in the stud it is reasonable they should regard a 

 horse with a nasal discharge with some degree of suspicion. 

 We offer this as a possible explanation of the fact asserted 

 by Hunting, of the rarity with which glanders is contracted 

 at the public water-trough, though in this matter it is fair 

 to say there are London practitioners who do not agree 

 with him. 



The length of time which elapses between infection and 

 clinical signs of the disease is most variable ; months, some- 

 times many months, pass after infection before there are 

 visible signs of the disease. 



The term clinical or visible signs of disease is of the 

 utmost importance. No one suggests that the virus lies 

 for months in the intestinal canal, and suddenly breaks out 

 in the lungs and nostrils ; but it may lie for months in the 

 lungs without giving any external indication, and there is 

 no doubt whatever that the risk of horses spreading glanders 

 when there is no clinical sign of disease is very slight; 

 indeed Hunting does not admit there is any risk even if the 

 lungs be ' studded with nodules,' but admits the danger of 

 the existence of such an animal, as local lesions may 

 develop very suddenly. 



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