PREVENTIVE MEDICINE 299 



and catarrh of mucous membranes of the conjunctiva and of the 

 upper part of the respiratory tract, and eruptive lesions of the skin. 

 Complications such as pneumonia, nervous symptoms, &c., often 

 appear during the course of or subsequent to the attack. Many 

 diverse organisms have been considered by different workers to 

 be the cause of distemper, but at the present time it appears to be 

 probable that these are secondary invaders. From the researches 

 of Carre in 1905* it seems that distemper is due to an ultravisible 

 virus. This view was confirmed by Lignieres and is accepted by 

 Hutyra and Marek. Carre found the virus to be present in the 

 blood, and especially in the serous nasal discharge in the early stages 

 of the attack. Such discharge, even after being passed through a 

 bacterial filter, reproduces the disease on subcutaneous injection. 

 The virus disappears from the nasal discharge, or at least cannot 

 be demonstrated therein at later stages of the attack. More recently 

 (1913) Torrey and Rahef have described an organism known as 

 the " Bacillus bronchisepticus " but it seems to be doubtful whether 

 it is the real cause. 



Dogs of any age are liable to attack, though young dogs are 

 more susceptible and the disease appears in them more frequently. 

 Its distribution is universal, and it is said to be especially prevalent 

 in wet chilly weather. The course of the disease is very variable. 

 Mild cases may recover in a week, though the average duration 

 is 3 to 4 weeks. The period of incubation was found by Carre 

 to be 3 to 4 days after artificial infection, but in natural cases it 

 is probably rather longer. The mortality varies within wide limits, 

 e.g., Gray $ considers that with Japanese spaniels it may reach as 

 high as 90 per cent, and gives the average for all dogs at about 

 25 per cent. 



The contagium is chiefly contained in nasal and ocular dis- 

 charges and, to a less extent, in the faeces and urine. Direct contact 

 between diseased and healthy dogs is probably the chief means 

 of spreading the disease, though the virulence of the contagium 

 and the resistance of individual dogs is very variable. According 

 to Hutyra and Marek, the virus most probably enters the body 

 per os along with food or water. Failure to diagnose the real 

 nature of the malady in its early stages is not infrequently followed 

 by the appearance of the disease in a healthy kennel, as, for instance, 

 in a veterinary infirmary. Kennel men undoubtedly spread the 

 disease in their own kennel by carrying the contagium on their 



* Revue Vet., Vol. V., p. 321. 



Mourn. Med. Research, Vol. XXVII., p. 291. 



t Wallis-Hoare, System. Vet. Med., Vol. I, p. 659, 1913. 



