DISEASES OF THE OX AND SHEEP. 321 



been passed through twelve or tifteen sheep it loses its efficacy, 

 but that at about the tenth remove a fluid is obtained which 

 produces a mild and not dangerous mahidy. The lymph may 

 be collected and stored in capillary tubes, afterwards hermetically 

 sealed at the ends, or ivory points may be charged and allowed to 

 dry. In time the lymph apparently becomes inert. The early- 

 formed lymph taken from small vesicles is the most pure, tran- 

 sparent, and viscid. If, after restoration to health, the patients 

 be again subjected to re-inoculation, or to the contagion itself, 

 no ill affects arise, inoculation being as powerful a preventive as 

 the natural disease itself. The animals should be kept quiet and 

 carefully attended to in regard to diet, and they should be 

 guarded against the vicissitudes of the weather, cold and 

 draughts, and so forth, provided with well-ventilated quarters, 

 well housed during the night, fed with good hay and coarse 

 meal, some of which last should be mixed with their water. If 

 the weather is mild and fine, the inoculated sheep may be allowed 

 to graze on tlie pastures and be out, even at night ; but when it 

 is cold and damp, they should certainly be sheltered and supplied 

 with nourishing diet. Should they be left out of doors in very 

 severe weather, those sheep which have been most strongly 

 affected will suffer greatly from local disturbances, great fever, 

 and diarrhoea which will generally lead to death. 



We have briefly described the process of ovination, as it was 



I known in 1848. 

 Vaccination has generally produced upon sheep only a local and 

 feeble action, very much less than that on the human body. It 

 does not seem to affect the general system of sheep. It is of no 

 Use to try to prevent sheep-pox by vaccination. It is supposed 

 that vaccination cannot be substituted for ovination. It has 

 not been found possible to communicate human small-pox to the 

 sheep. The conveyance of human small-pox to the ox is said to 

 engender the true vaccine. Vaccine matter having failed in 

 Egypt, it was found that by inoculating the cow with small-pox 

 from the body, fine active vaccine virus is produced ; but it really 

 requires to be humanized before it can be depended upon. 

 Whether the product of the natural ovine vesicle can be substi- 

 tuted for the vaccine is very doubtful. Some hold that the 

 transmission of tlie ovine lymph to the ox tribe is the best means 

 of rendering it more suited for the inoculation of sheep, and it 



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