DISEASES OP THE BLOOD. 179 



acquainted. The epizootic attack of influenza seems to 

 extend in a definite direction witli varying rapidity ; from 

 the subtle nature of the poison it is difficult to guard 

 against. It affects the majority of animals in a neighbour- 

 hood, and often its progress in the system is marked by 

 extreme and rapid debility. It has been observed in 

 islands, whither it must have been conveyed by the air, 

 since they have not been visited from the mainland during 

 an outbreak. Many of the phenomena of these affections may 

 be explained on the theory of clouds of disease-producing 

 bodies in the air. One of the most remarkable of the diseases 

 of this nature is enteric fever of man. It can generally 

 be associated with ingestion of impure water polluted with 

 the filterings of drains and cesspools, the intermediary 

 phase of the disease-generating organism being passed in 

 human ejecta. Some have attributed outbreaks of this 

 disease among men to consumption of diseased milk, and 

 also of diseased flesh, but the diagnosis of enteric fever 

 in man is not accurate. Trichinosis, for instance, is 

 mistaken for it, and is liable to be confounded with any 

 gastro- enteric disturbance. Where there could have been 

 no doubt about the diagnosis, the typhoid or enteric fever 

 has been traced to polluted water admixed with the milk. 

 When influenza is prevalent as a panzootic it is said to 

 sometimes affect the ox, but the most remarkable influen- 

 zoid disease of cattle is known as malignant cataeeh, 

 COEYZA, or " glanders '' (but with the disease of the same 

 name affecting the horse it has not the slightest relation). 

 It is a specific febrile disorder, the lesions of which are 

 most marked on the mucous membrane, especially that of 

 the facial sinuses. It is non-contagious, and generally 

 affects only two or three animals in a herd. Old animals 

 seldom, if ever, suffer from it. Fever is marked at the 

 commencement, but later there is extreme prostration and 

 the animal dies asphyxiated. The visible mucous mem- 

 branes are purple and dry, and later tend to undergo 

 ulceration. There is an abundant flow of saliva from the 

 mouth in the early stages, and the bowels are torpid, but 

 soon diarrhoea sets in, the urine becomes offensive, and 



