PATHOLOGY. 703 



various indigestible substances, as glass, iron and 

 wood, utters pathognomonic (?) long-drawn-out 

 howls, may become ferocious, or, on the other 

 hand, quiet and sullen. At autopsy the meninges 

 and nervous tissue are congested if the disease is 

 advanced, and the indigestible substances men- 

 tioned may be found in the stomach, although the 

 latter finding has little or no diagnostic importance. 



A number of histologic changes have been de- 

 scribed as characteristic. Among these are the 

 bodies of Negri, described above. Remlinger at- 

 taches a great deal of importance to them as a 

 means of diagnosis. Babes describes perivascular 

 nodules of lymphoid cells (Wutknotchen) in the 

 medulla and cord. The lesion of Van Gehuchten 

 consists of a proliferation of the endothelial cells 

 (neuronophages) surrounding the ganglionic cells, 

 the latter at the same time undergoing atrophic 

 and degenerative changes. This change is most 

 marked in the cervical ganglia. One group of ob- 

 servers finds these lesions constant in animals 

 which have died of hydrophobia, but they may be 

 absent if the animal is killed during the course of 

 the disease; hence their absence does not exclude 

 the diagnosis of hydrophobia. Others have found 

 similar changes in other diseases. Metchnikoff, 

 it will be remembered, observed the destruction of 

 ganglionic cells, by neuronophages in aged dogs 

 (page 309). 



We are hardly able at present to consider these 

 changes as pathognomonic. Particularly in early 

 stages of the disease they may be absent. The bite 

 of a rabid dog is infectious in from two to four 

 days in advance of the development of symptoms, 

 and autopsy performed at this time may show 



