Variola : Pox. 337 



(inoculation) while in smallpox and sheeppox, infection may take 

 place at some distance from the patient (in sheep over 200 yards). 



A particulate infecting material was demonstrated by Chauveau, 

 who filtered the virus and inoculated the filtered liquid without 

 effect, while the solids retained on the filter invariably produced 

 the disease. 



The identity of the microbe of variola has been much dis- 

 cussed, Guttmann and Grigorjew found in the lymph a coccus 

 (Staphylococcus albus variolse)', Ruete a very motile diplococcus, 

 and others streptococcus, but in cutaneous lesions it is very diffi- 

 cult to exclude such elements. Pfeifler, Guarnieri, Van derLoeff, 

 Wasielewski and others have drawn attention to small proto- 

 plasmic bodies (manifestly protozoa) found in the vaccine lymph, 

 and which appear to be the infecting agents. Wasielewski culti- 

 vated these on a rabbit's cornea to the 48th generation, and from 

 the last successfully inoculated a calf and several children. 



Funck finds this sporidium vacdnale constantly in the vaccine 

 lymph and surrounding tissue, as a refractile, amoeboid, spherical 

 organism (spore) i to 3/x. in diameter, and, less abundantly, 

 a round or ovoid spore cyst 25/x. These cysts are either smooth, 

 or uneven like a raspberry, and have a single or double contoured 

 membrane. They are easily stained with Sudan III. Examined 

 in hanging drops they are seen just under the cover glass, not on 

 the surface of the drops. Larger flattened bodies found in the 

 lymph, with many included spores are manifestly epithelial cells. 

 Copiman cultivated the organism in glycerinated collodion cap- 

 sules in the peritoneal cavity of rabbits and dogs, producing zoog- 

 loea masses staining peripherically with methylene blue, and 

 which caused typical vaccinia in calves. He found the same ele- 

 ments in variola of man. 



HORSE POX. VARIOLA EQUINv^. 



This was recognized toward the end of the i8th century, in the 

 valley Of the Severn, England, by Jenner, who believed it to be 

 the origin of cowpox, but failed apparently to distinguish it from 

 ordinary ''^grease'". Today, when we must trace each case to a 

 preexistent one in some animal, and ignore the question of pri- 

 mary origin, we must still recognize that it passes readily from 

 horse to cow,' and from cow to horse, through the hands of milk- 

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