RABIES 293 



true rabid and ''suspected" dogs, the proportion is reduced to about 8 

 per cent. 



The most dangerous bites seem to be those directly into a nerve or upon 

 nerve tissue, even if it is on the smaller branches of nerves, whereas a bite 

 on blood vessels or the lymphatic system is less so, and artificial inoculation 

 proves that if it is made as near to the central nervous system as possible 

 the disease makes its appearance more quickly, and the injection directly 

 on the dura mater produces the disease in shorter time and more certainly 

 than any other part of the bod}-. Pasteur claimed that if there is the 

 largest proportion of virus in the brain, it produces furious rabies, and if 

 the virus predominates in the spine it causes dumb rabies. It is possible 

 that the results of the material changes on the animal economy produced 

 by the disease ''toxines" may have some effect on the character and 

 severity of the disease, the nature of which is at present really not 

 known. Anrep prepared a serum from the brain of guinea-pigs affected 

 with furious rabies; this serum injected into animals produced lowering of 

 temperature, paralysis of the extremities, salivation, and death by para- 

 lysis of the respiratory centres. 



Pathological Anatomy. — The post-mortem results are generally nega- 

 tive and vary in different animals, but, as a rule, specific alterations are 

 noticed. These are as follows: 



Great emaciation with very distinct muscular rigidity and a rapid 

 tendency to decay; collections of mucus upon all the natural orifices, 

 such as the mouth, nose, and the prepuce; prominence of the cutaneous 

 veins, which are found to be filled with thick, imperfectly clotted blood; 

 redness and swelling of the mouth and mucous membranes. The throat 

 is covered with a whitish-gray mucous exudation; intense inflammation of 

 the glands of the pharynx; in some cases slight swelling and hyperaemia of 

 the salivary glands. In the cavity of the throat and mouth we find for- 

 eign bodies, such as hair, straw, coal, wood, etc.; they may also be found 

 in the oesophagus, which is frequently very red and covered with clammy, 

 gray mucus. This condition is seen in the stomach which contains little 

 or no food but, as a rule, numerous indigestible objects of various kinds 

 and sizes — straw, hair, wood, stones or pieces of leather or rags. The 

 mucous membrane is reddened and swollen, especiall}' on the surface of its 

 folds, and marked with hemorrhagic erosions, which Johne describes as 

 sepia-colored. The intestine may be empty or it may contain some of the 

 foreign bodies. The mucous membrane of the pharynx is always very 

 red, swollen, and covered with mucus in its anterior portions. These alter- 

 ations are also seen in the trachea and the large bronchia. The lungs are, 

 as a rule, filled with blood, but otherwise normal. In rare instances we 

 find circumscribed centres of irritation due to foreign bodies being inhaled 

 through the bronchial tubes. The heart and its envelope are generally 



