50 THE DISEASES Otf THE DOG. 



but unsuccessfully, and the same result has followed com- 

 parison of it with influenza of the horse and strangles. 

 Possibly through confusion between this disease and true 

 variola, the idea has spread abroad that vaccination is a 

 preventive, but it is erroneous. All the phenomena of 

 distemper are traceable to an altered condition of the 

 blood, and Semmer of Dorpat, who has investigated the 

 disorder on modern methods, comes to the conclusion that 

 that fluid contains a special bacterium of the micrococcus 

 form. When the blood becomes contaminated with the 

 distemper poison almost every tissue in the body may 

 become the seat of asthenic manifestations, and according 

 as the symptoms are most intense in any one system of 

 organs has the disease been considered to assume a spe- 

 cial type, such as the hepatic, pulmonary, intestinal, 

 cerebro- spinal, or catarrhal. It is not evident to what 

 the occurrence of either qf these types in any particular 

 case is traceable, but it is remarkable that when the 

 disease is prevailing in an epizootic, form some one special 

 type markedly predominates. Certain conditions of the 

 system seem to favour the development of the disorder, 

 which in this respect resembles strangles of the horse ; 

 thus the young are especially liable to suffer, but it 

 may occur in animals of any age ; also it is especially 

 frequent among foreign animals, more particularly those 

 recently imported, and it is most severe in type and 

 symptoms in animals which are subjected to specially 

 artificial systems of management. Various defective 

 sanitary conditions, such as damp, ill-drained kennels, too 

 low feeding, want of light and fresh air, and no exercise, 

 have been considered to generate it spontaneously, but 

 this view must be received with the greatest caution. 

 Such influences certainly render animals liable to attack, 

 but the contagium of the disease is so wide spread, and 

 its communicable nature so little recognised among people 

 in charge of dogs, that we ought to hesitate before con- 

 sidering this specific disorder as capable of originating 

 spontaneously. It is well worthy of inquiry whether in 

 everyday practice there are not several distinct disorders 



