182 ANNUAL REPORTOF THE Off. Doc. 



Horses — 21 to DO days. 



Swine, sheep & ji^oats— 21 to 60 days. 



Birds— 14 to GO da vs. 



Kabhits— to 00 days. 



Guinea y^igs — 8 to GO days. 



It is an exceedingly rare occurrence for men or any of the lower 

 animals to develop rabies following the 100th day from the time of 

 exposure or infection, but there are rare instances in which excep- 

 tionally long periods of incubation have been observed. 



SYMPTOMS 



A careful study of the symptoms of rabies in the dog is of the 

 greatest importance in attempting an antemortem diagnosis. The 

 disease is acute in its course, and when symptoms are pronounced, 

 death usually follows in a very high percentage of cases within several 

 days. Pasteur, IIous and Babes are on record as having seen rabies 

 in the dog with recovery after well marked symptoms had developed. 

 These instances are exceedingly rare and should not detract from 

 the general opinion that rabies is always fatal. In a careful observa- 

 tion of a large number of dogs suspected of having rabies, sent to 

 the Veterinary Hospital of the School of Veterinary Medicine of 

 tlie rniversify of Pennsylvania during 1906-1909, inclusive, not one 

 dog lived more than eight days with symptoms of the disease. 



The types or forms of rabies are usually recognized — the furious 

 or irritable types are not sharply defined nor always separable. They 

 are more (■(irr(^ctly cniisidercd as stages of the disease because both are 

 preceded by identical premonitory symptoms. The furious stage is 

 usually followed by the paralytic stage; b\it not infrequently the 

 paralytic stage may follow the premonitory symptoms with the 

 omission of the furious stage. 



PREMONITORY SYMPTOMS 



First, a decided change in the disposition of the animal is ob- 

 served. A lively and amiable dog may suddenly become dull; the 

 quiet and unexcitable dog may become unusually alert, more affec- 

 tionate, demonstrative and exhibit the desire to be caressed. A dog 

 not in the habit of barking, may bark frequently without any ap- 

 parent reason and seem unduly disturbed without cause. The ap- 

 petite is good and even excessive, and ]>erhaps the animal may eat 

 food as a rule not enjoyed. The increased fi-iendliness is most strik- 

 ing, and other changes in the disposition may be detected. Thes'3 

 symptoms may suddenly become more alarming, as the furious stage 

 succeeds tlie premonitory symptoms, or the dog may seek quiet sur- 

 roundings Avith the development of the paralytic or dumb stage. 



FURIOUS STAGE 



The dog is increasingly restless. The muscles are firmer and more 

 tense, particularly those of the limbs and back. He responds to the 

 owner's call, but not quietly. The impression is that the dog has 



