396 DISEASES OF CATTLE. 



feet, with an insane tendency to attack other animals, although the 

 desire to bite is not so marked in cattle as in the canine race. A con- 

 stant symptom is the increased secretion of saliva with a consequent 

 frothing at the month, or the secretion may hang from the lips in long 

 strings. Constipation is marked, and there is manifested a continual, 

 although unsuccessful, desire to defecate. Spasms of the muscles in 

 different parts of the body are also seen at intervals. About the 

 fourth day the animal usually becomes quieter and the walk is stiff, 

 unsteady, and swaying, showing that the final paralysis is coming 

 on. This is called the paralytic stage. The loss of flesh is extremely 

 rapid, and even during the short course of the disease the animal 

 becomes exceedingly emaciated. The temperature is never elevated, 

 it usually remaining about normal or even subnormal. Finally, there 

 is complete paralysis of the hind quarters, the animal being unable 

 to rise, and but for irregular convulsive movements lies in a comatose 

 condition, and dies usually from the fourth to the sixth day after the 

 appearance of the first symptom. 



Anatomy. — If animals which have succumbed to rabies be exam- 

 ined postmortem, very slight evidence of disease will be found in any 

 of the organs, and, indeed, the absence of any specific lesions may be 

 considered as characteristic. The blood is dark and imperfectly 

 coagulated. The throat is frequently reddened, and there may be 

 small spots of extravasated blood in the intestines. The stomachs 

 are usually empty. In the spleen there may be hemorrhagic enlarge- 

 ments (infarcts). The cadavers rapidly undergo decomposition. 



Differential diagnosis.'— It is not an easy matter to decide definitely 

 that a given animal has rabies, since the symptoms given above belong 

 in part to a variety of other diseases, among which may be mentioned 

 the excitement seen in young animals following close confinement, 

 certain vegetable and mineral poisons, acute enteritis, and alterations 

 of the central nervous system in cattle, the most common of which is 

 tuberculosis of the brain and its covering membranes. However, the 

 postmortem lesions should assist in making a correct diagnosis. 

 Tetanus may readily be differentiated from rabies by the persistence 

 of muscular cramps, especially of the face and abdomen, which cause 

 these muscles to become set and as hard as wood. In tetanus there 

 is also an absence of a depraved appetite or of a wilful propensity to 

 hurt other animals or to damage the surroundings. The cow remains 

 quiet and the general muscular contraction gives the animal a rigid 

 appearance. There is an absence of paralysis which marks the 

 advanced stage of rabies. The dumb form of rabies in dogs is char- 

 acterized by the paralysis and pendency of the lower jaw, while in 

 tetanus the jaws are locked. This locking of the jaws in cattle ren- 

 ders the animal incapable of bellowing as in rabies. Finally, tetanus 

 may be distinguished from rabies by the fact that the central nervous 

 system does not contain the infectious principle, while in rabies the 



