308 THE PATHOGENIC RHIZOPODA 



cinicB, and in smallpox, Cytorydes variolas, but they were much more 

 often referred to in subsequent investigations as the Guarnieri bodies. 

 To Guarnieri, therefore, belongs the credit of placing smallpox and 

 vaccinia among the experimental diseases, and the stimulus given by 

 his work had an immediate effect. The majority of later investigators 

 w r ere opposed to his conclusions, although many, including Pfeiffer, 

 Ruffer, and Plimmer, Clark, Monti, Wasielewsky, and others, believed 

 that the parasitic nature of the inclusions had been demonstrated. 

 The opponents based their criticisms upon the facts that no ameboid 

 movement could be observed, nor division phases, nor cellular struc- 

 tures (Hiickel, Foa, Mann, etc.), and they interpreted the Guarnieri 

 bodies as special secretions or degenerations resulting from a peculiar 

 transformation of a portion of the cell plasm under the stimulus of 

 the vaccine virus. Wasielewsky, in 1901, brought new support to the 

 view of Guarnieri by passing vaccine virus through forty-eight suc- 

 cessive transplantations, the thirty-sixth giving a successful vaccination 

 against smallpox. In each case the same inclusions were present in 

 the epithelial cells and in approximately the same number, indicating 

 that reproduction must have taken place. In 1903 Councilman, in 

 cooperation with seven other investigators, published an exhaustive 

 monograph on the pathology and etiology of smallpox, covering all 

 phases of the pathology of the disease, Brinckerhoff and Tyzzer 

 extending the experimental investigations of Guarnieri and Wasie- 

 lewsky to apes, and Calkins working out a tentative life history of 

 the parasite. Howard, in 1905, confirmed, independently, all of the 

 findings of Councilman and co-workers, and identified every stage of 

 life history of the organism. 



So far as the organism is concerned, the most important discovery 

 of these investigators was made by Councilman, Magrath, and 

 Brinckerhoff, who found that in variola the inclusions are present both 

 in the cell bodies and in the nuclei, while in vaccinia they are present 

 only in the cell bodies. Councilman concluded that the intranuclear 

 position indicates a phase in the life history of the parasite which is 

 absent in the vaccinia cycle, and that this phase is responsible for the 

 greater malignancy of smallpox. 



Calkins interpreted the parasite as a sporozoan belonging to the group 

 of microsporidia, and, as it now appears, gave an unnecessarily compli-. 

 cated account of the life history. Minchin('OG) regards it as more closely 

 related to the haplosporidia, because of the absence of polar capsules 

 and threads. The tentative life history worked out by Calkins was 

 formulated before the observations on the chromidia of rhizopods 

 were made and before the importance of this material of the cell was 

 established. In the light of our present knowledge it is much more 

 probable that the Guarnieri bodies are rhizopods, and that the com- 

 plicated changes which were earlier interpreted as pansporoblast 



