INFECTIOUS DISEASES OF CATTLE. 413 



jaw, while in tetanus the jaws are locked. This locking of the jaws 

 in cattle renders the animal incapable of bellowing as in rabies. 

 Finally, tetanus may be distinguished from rabies by the fact that 

 the central nervous system does not contain the infectious principle, 

 while in rabies the inoculation of test rabbits with the brain or cord 

 of a rabid animal will produce the disease with characteristic symp- 

 toms after an interval of 15 to 20 days. This period of incubation 

 is much longer than in tetanus, since the inoculation of rabbits with 

 tetanus cultures invariably results in death after a short period and 

 usually within three days. The positive evidence that a rabid dog 

 has been near cattle would greatly assist in making a decision in 

 doubtful cases. 



The disease in dogs is pretty well recognized by most people, but in 

 case a suspected dog is killed it is desirable to open the animal and 

 examine the contents of the stomach. AATiile food is absent, a variety 

 of odd things may be present which the abnormally changed appetite 

 of the rabid dog has induced it to swallow. Among such things may 

 be straws, sticks, glass, rags, earth, pieces of leather, and whatever 

 the animal may have encountered small enough to be swallowed. 

 This miscellaneous collection in the stomach of dogs, together with 

 absence of food, is regarded by authorities as a very valuable sign, 

 and may be made use of by laymen in case of doubt. In important 

 cases, however, the head of the dog, cow, or other suspected animal 

 should be removed and sent to the nearest biological laboratory, 

 where a positive diagnosis can be made within 30 liours by the histo- 

 logical examination of the plexiform nerve ganglia, and within two 

 or three weeks by the intracerebral inoculation of rabbits with an 

 enndsion of the brain of the suspected animal. 



T retdTYi^nt. — This is useless after the first appearance of S3'mptoms. 

 When, however, a wound inflicted by a rabid animal can be discov- 

 ered, it should be immediately cauterized or even completely extir- 

 pated, care being taken to cut entirely around the wound in the 

 jiealth}' tissues. For cauterizing the wound, fuming nitric acid, the 

 hot iron, and 10 per cent solution of zinc chlorid are the most effica- 

 cious. To afford an absolute protection, this should be done within a 

 few moments after the bite has been inflicted, although even as late 

 as a few hours it has been known to thwart the development of the 

 disease. 



Pasteur has originated and perfected a system of preventive inocu- 

 lation against this disease which has greatly reduced the mortality in 

 human subjects. Its application to animals, however, is more diflS- 

 cult, requiring considerable time and expen.~e, and is therefore only 

 economically applicable in cases where A'ery valuable animals are bit- 

 ten by dogs known to be mad. Sanitary regidations which seek to 

 control effectively the disease by exterminating it among dogs are 



