ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 97 



susceptibility to bovine plague is nearly the same as the buffalo, in 

 Indo-China at all events. 2. yoVtr c.cm. of virulent blood constitutes 

 a certain lethal dose. 3. ^3-^ot5' c.cm. of blood is the smallest infective 

 dose. 4. yV c.cm. of plasma is comparable to the minimal lethal dose. 

 5. The virus of bovine plague resides in the leucocytes, though it is 

 sometimes found free in the plasma. 6. There are about 25,000 

 microbes, or groups of microbes, per c.cm. in the whole virulent blood. 

 7. There are about 10 organisms per c.cm. in the centrifuged citrated 

 plasma. 8. Sensitization of the virus has not given good results in the 

 author's hands. 9. Anti-pest serum does not act upon the virus itself 

 but upon the organism of the experimental animal. 10. " Sero-infection " 

 appears to give good results with the buffalo, provided a sufficient 

 quantity of serum is injected {^Q c.cm. per 100 kilos, body-weight for 

 adults, more for young animals), and infecting with the least possible 

 quantity of virus, in order to retard the rapid growth of the parasite. 



Vitality of Rinderpest Virus outside the Animal Body.* — A. W. 

 Shilton has carried out a series of elaborate investigations, at Muktasar 

 in Northern India, with reference to the viability of the rinderpest 

 virus outside the animal body under natural conditions, and has come 

 to the following general conclusions : — 



1. At the Muktasar Laboratory rinderpest infection was found to 

 persist in certain buildings for forty-eight hours after the removal of sick 

 animals, but not for longer periods of time ; frequently infection was 

 absent after shorter intervals. Ground which was shaded by trees, when 

 contaminated by cattle suffering from rinderpest, was found to be 

 infective to healthy stock eighteen hours after the removal of the sick 

 animals, but not for longer intervals. Ground entirely exposed to direct 

 sunlight did not remajn infective beyond eight hours. 



2. In the plains, buildings were found to remain infective for twenty 

 hours after the removal of the sick animals, but non-infective after 

 longer intervals. Areas shaded by trees remained infective for twenty- 

 four hours, and those exposed to direct sunlight for six hours after the 

 removal of the sick animals, but not for longer periods of time. 



3. The rinderpest virus was found to survive in mixed faeces and 

 urine protected from direct sunlight for periods of fifty-four hours 

 after excretion by sick animals, but when exposed to direct sunlight 

 the. virus did not survive for longer periods than eight hours. Saliva 

 and nasal discharge from sick animals did not remain infective beyond 

 forty-four hours. 



4. It may be concluded, therefore, that in buildings and on areas 

 infected by the natural discharges of sick animals, the rinderpest virus 

 is unable to survive for more than two or three days, and when air 

 and sunlight are freely admitted its destruction is even more rapid. 



5. The carcases of animals which have died from the disease must, 

 however, be regarded as possible sources of infection for some consider- 

 able time after death, especially when the air-temperature is low, as it 



* Mem. Dept. Agric. India, Veterinary Series, iii. No. 1 (1917). 

 March SOth, 1918 H 



