PATHOLOGY OF HYDROPHOBIA 511 



more common. After a period of incubation of from three to 

 six weeks, the first symptom noticed is a change in the animal's 

 aspect ; it becomes restless, it snaps at anything which it touches, 

 and tears up and swallows unwonted objects ; it has a peculiar 

 high-toned bark. Spasms of the throat muscles come on, 

 especially in swallowing, and there is abundant secretion of 

 saliva ; its supposed special fear of water is, however, a myth, 

 it fears to swallow at all. Gradually convulsions, paralysis, 

 and coma come on ; and death supervenes. In the paralytic 

 form, the early symptoms are the same, but paralysis appears 

 sooner. The lower jaw of the animal drops, from implication 

 of the elevator muscles, all the muscles of the body become 

 more or less weakened, and death ensues without any very 

 marked irritative symptoms. 



In man the incubation period after infection varies from 

 fifteen days to seven or eight months, or even longer, but is 

 usually about forty days. When symptoms of rabies are about 

 to appear, certain prodromata, such as pains in the wound and 

 along the nerves of the limb in which the wound has been 

 received, may be observed. To this succeeds a stage of nervous 

 irritability, during which all the reflexes are augmented the 

 victim starting at the slightest sound, for example. There are 

 spasms, especially of the muscles of deglutition and respiration, 

 and cortical excitement evidenced by delirium may occur. On 

 this follows a period in which all the reflexes are diminished, 

 weakness and paralysis are observed, convulsions occur, and 

 finally coma and death supervene. The duration of the acute 

 illness is usually from four to eight days, and death invariably 

 results. The existence of paralytic rabies in man has been 

 denied by some, but it undoubtedly occurs. This is usually 

 manifested by paralysis of the limb in which the infection has 

 been received, and of the neighbouring parts ; but while in such 

 cases this is often the first symptom observed, during the whole 

 of the illness the occurrence of widespread and progressive 

 paralysis is the outstanding feature. In man then also occur 

 cases where the cerebellum and also the sympathetic system seem 

 to be specially affected. 



The Pathology of Hydrophobia. In hydrophobia as in 

 tetanus, to which it bears more than a superficial resemblance, 

 the appearances presented in the nervous system, to which all 

 symptoms are naturally referred, are comparatively unimportant. 

 On naked-eye examination, congestions, and, it may be, minute 

 haemorrhages in the central nervous system, are the only features 

 noticeable. Microscopically, leucocytic exudation into the peri- 



