No. 6. DEPARTMENT OF AGRICULTURE. 515 



three daj^s, of slieei^ buried tliirty-'Hie days, and of dogs buried forty- 

 four days. Other observers have found it still active in animals 

 buried for twenty-four days. 



It is destroyed couiplclely by a temperature of 50 degrees C. (122 

 degrees F.) in one hour, or GO degrees C. (140 degrees F.) in one-half 

 hour. It i« uninjured by exposure to extreme cold, resisting the 

 prolonged application of a temperature from 10 degrees to 20 degrees 

 below zero, centigrade. 



Ks activity is destroyed in one hour by a 5 per cent, solution of 

 carbolic acid, or by a 1 to 1,000 solution of corrosive sublimate. 

 Wate"' saturated with iodine destroys it in ten minutes. 



Danger from Bites. The danger of infection as well as the time 

 elapsing between the introduction of the poison and the development 

 of the disease is dependent upon a number of factors. The disease 

 appears more quickly in children than in older persons, and for 

 obvious reasons they are more often attacked by dogs, and the 

 bites are more apt to be on the face and head. Wounds about 

 the head and face are i)articularly dangerous, next comes bites about 

 the hands, and lastly, other parts of the body. The richer the 

 nerve supply of a part the greater the danger. Punctured wounds 

 are most dangerous, and lacerated wounds are dangerous in propor- 

 tion to the extent of the surface afforded for the absorption of 

 the virus. The danger of infection varies with the animal which 

 inflicts the bite. First, comes the wolf; second, the cat; third, the 

 dog, and, fourth, other animals. In the western part of the United 

 States the skunk is said to be very liable to the disease, and the 

 bite from this animal is quite dangerous. Bites on naked or ex- 

 [losed parts of a person are more dangerous than through cloth- 

 ing, in the latter case the virus being wiped off and not gaining ac- 

 cess in quantity to the tissues. The same thing is observed among 

 the lower animals, as dogs with long hair, like the spaniel and 

 the collie, are less liable to the disease than are short-haired dogs. 

 Experimentally, it has been shown that rabbits which are shaven 

 and exposed to the bite of a mad dog are more often affected than 

 are those bitten through the fur, even when the teeth penetrate 

 deeply beneath the skin. The proportion of persons who contract 

 hydrophobia after being bitten by mad dogs, and are not treated, 

 is conservatively estimated at 16 per cent., but some series of cases 

 give a much higher mortality. Thus, of 855 cases collected by Tar- 

 dieu, Thamhayn and Bouley, 300 ended in death, or 4G.G per cent. In 

 another series of cases given by Bouley, out of 2GG persons bitten, 

 152 died of hydrophobia; but of these. 120 were bitten on the face and 

 hands, the greatei- danger from which has been mentioned. 



The mortality following bites from wolves is placed at from GO to 

 80 per cent., the increased danger from these animals being due 



