DIAGNOSIS 323 



rabies the inoculation wound in the head should be healed 

 perfectly, there should be no abscess and the meninges should 

 be free from exudates and the brain itself should appear per- 

 fectly normal, except that in rare cases there may be a slight 

 injection of the blood vessels. The viscera are ordinarily 

 normal in appearance, with possibly the exception of the liver, 

 which we have frequently found to be deeply reddened and 

 the gastric mucosa, which not infrequently shows dark patches, 

 indications of disintegrated hemorrhagic areas. A bacterio- 

 logical examination fails to reveal the presence of micro- 

 organisms in either the tissues 01 blood. Another important 

 point which has been noticed is an intense rigor mortis follow- 

 ing death from rabies. Kinyoun states that this was a con- 

 stant feature of this disease in all of the produced cases which 

 have come under his observation. Wesbrook has not found 

 this condition. 



Animals other than rabbits have been used and a number 

 of other methods of inoculation have been proposed. 



Diag)iosis by histological examiiiation. The rapid diagnosis 

 by means of the histological changes pointed out by Van 

 Gehucten and Nelis has been very successful in the experience 

 of Ravenel. He states that : "The ganglion of the pneumo- 

 gastric nerve is selected by preference and should be removed 

 as soon as possible after the death of the animal. It is put 

 into absolute alcohol or ten per cent formalin solution. If put 

 into absolute alcohol it should be removed to a fresh portion 

 of alcohol at the end of six hours, in which it rem.ains for six 

 hours, when it may be transferred for one hour to a mixture of 

 absolute alcohol and chloroform, and then put for one hour in 

 pure chloroform, then for one hour in a mixture of chloroform 

 and paraffin, and lastly imbedded in paraffin. If formalin is 

 used for fixing, the ganglion should be removed at the end of 

 six or eight hours, put for six hours more in 95 per cent 

 alcohol and then into absolute alcohol for six hours, after 

 which it ma}' be fixed in blocks for cutting, by mucilage or 

 gum arable, or else imbedded in collodion. The characteristic 

 ■changes of the capsule are brought about best by the use of 

 Jiematoxylin, or hemalum and eosin. The method of Nissl 



