Progress of Rational Pathology. 243 



small-pox : but Conradi and others have clearly proved by 

 facts, that this is not the case. As to the question whether 

 cow-pox is of the same origin as the small-pox of man, the 

 results of Wedekind, Sunderland, Numann, and others, who 

 tried to produce cow-pox by means of the atmospheric conta- 

 gion of small-pox, are all contradictory. The identity of 

 variola and of vaccine must, no doubt, be granted ; but it is 

 still doubtful, whether the pox in cows was at first and 

 is still produced by contagion of small-pox only, or whether 

 it can develop itself independently in the animals. By 

 inoculating variolous matter into the udders of cows, Ceely 

 and Thiele produced an eruption, which when inoculated back 

 into men, appeared to be a powerful vaccine. Indeed the 

 virus of small-pox may be altered to vaccine by inoculating 

 with variolous lymph mixed in warm cow's milk, after it has 

 lain for a few days between plates of glass secured by wax : 

 if the experiment be continued, after the fifth reproduction, 

 fever will cease to attend its inoculation ; and after the tenth 

 reproduction, we may inoculate in the ordinary way from arm 

 to arm. Gruby has discovered microscopic beings in the 

 papulae and vesicles among the elements of the pus — pox- 

 animalcules. They consist of a globular or conical body 

 and a fine neck with a small hook, which they keep constant- 

 ly moving, while they bend their neck backwards and for- 

 wards, and at times pull it back entirely. They are as large 

 as molecular corpuscles, and Henle suspects that they are 

 perhaps only such. — Sheep-pox. Several ewes in lamb were 

 inoculated, almost all the foetuses had pocks, and some of 

 the sheep produced lambs covered with pocks : pox in sheep 

 appears to have the same antipathy to the itch as human 

 small- pox has. 



b. Measles. — When Catona inoculated with the fluid of the 

 vesicles of measles mixed with blood, or with the tears during 

 the height of the eruption, the inoculation took effect in all but 

 7 out of 100 patients : a red ring formed round the point 



