SMALL POX 26l 



Certain protozoonoid bodies have been seen by numerous ob- 

 servers, notably by VanderLoeff, L. Peiffer, and Guarnieri. The 

 latter gave the name Cytoryctes vaccinias s. variolas. In the 

 deep layers of the epithelial cells of the pustules of vaccinia and 

 small-pox, in the experimental lesions on the corneae of rabbits, 

 and in the protoplasm of the cells, these bodies are found. They 

 are about the size of a micrococcus and exhibit amoeboid move- 

 ments in hanging-drop preparations. They are perfectly char- 

 acteristic of the lesion produced in vaccinia and are not found in 

 other diseased conditions. 



In variola many different changes occur in the appearances of 

 these cytoryctes, suggesting developmental cycles. 



In variola they are often intranuclear, while in vaccine they are 

 never found within the nuclei. 



The cycle of development is suggestive of the development 

 of many of the protozoa. Stages of development exhibiting 

 fusiform amoeboid shapes can be seen, and pseudopodia can be 

 detected in the process of developmental stages suggestive of 

 gametocytes; the union of the gametes and the ultimate forma- 

 tion of the zygote can also be discerned. 



After the tenth day these bodies cannot be very well discerned 

 in the tissues. 



There is reason to think that the parasites circulate in the blood 

 in variola. The contagion in variola is thought to be by inhala- 

 tion. It is certain that the disease can be produced by inocula- 

 tion with virus from a case of small-pox. The contagion exists 

 in the scales, pus cells, and excretions of patients ill with small-pox. 



If the virus of small-pox is introduced into a monkey, and then 

 into a cow the disease produced is not variola, but vaccinia 

 (Monkman). The hypothetical organism above described, cyto- 

 ryctes, becomes attenuated in the cow, so that it is incapable of 

 producing variola, but vaccinia. 



Rabbits, horses, and sheep are susceptible of inoculation with 

 the virus of vaccinia (see Vaccination). Virus may be tested by 



