SMALL-POX AND VACCINIA 49 



later sporing forms with bodies I saw in small-pox tissue ten years 

 ago. The earlier intranuclear forms closely resemble those struc- 

 tures to which in 1895 I drew attention in a sarcoma of the breast, 

 and suggested that both they and the parasites of variola possibly 

 belonged to that subdivision of the protozoa called Suctoria^jnany 

 of which are intranuclear parasites.' 



Minchin provisionally places the cytoryctes among the sporozoa 

 incertcz sedis. 



This view of the pathology of small-pox may now be briefly stated. 

 From some primary point of entrance into the tissues of the body 

 (most probably in the alimentary or respiratory tract, possibly from 

 a flea-bite or some such source) the cytorycte in some minute form 

 (? Doehle's flagellates) enters the blood, and is distributed to all the 

 organs of the body. The chief ocular evidence of this generalized 

 infection is in the skin and fauces, where the organism is found in 

 the papules as the now familiar form of the minute amoebae in the 

 epithelial cells. In the amceboid cytoplasmic stage the parasites 

 multiply for a time, passing through several generations (Fig. 13 ; 

 / to 5). In vaccinia the process is limited to this stage, but in variola a 

 different stage, the intranuclear, occurs. The intranuclear stage is 

 first recognisable as amceboid structures (Fig. 13 ; 6). These become 

 rounded off (Fig. 13 ; P), and, according to Calkins, male and female 

 forms (male and female gametocytes) are to be distinguished, the 

 end of the process being the formation of minute, highly refracting 

 bodies. I have been able to identify the bodies described by Calkins 

 in preparations that he kindly gave me in 1904. The various bodies 

 require close and leisured attention for their recognition. I am not 

 in a position to criticise the author's view as to the biological cycle 

 of the parasites, but I must observe that I met with bodies exactly 

 resembling some of those he describes as sporoblasts in appearance, 

 but on a much larger scale (and hence more easily studied), in the 

 alveolar sarcoma of the human breast described below (Chapter XII.). 

 A closer study of these showed them to be tentaculiferous, and 

 some portion of their life-history will be described below. It may 

 be ultimately found that the parasites in the intranuclear stage of 



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