Scientific Proceedings. 



(Hz) 53 



insensibly into the other, as to force the conclusion that these par- 

 ticular bodies have arisen by recent extrusion of nuclear chromatin 

 into the cytoreticulum. Other bodies are disconnected from the 

 nucleus and these may have arisen partly from the chromatin of 

 the cytoplasm, a possibility which is furnished by Hertwig's theory 

 of the constitution of cell protoplasm. Many of the vaccine bodies 

 closely resemble the chromidial substance described by Hertwig 

 in some lower animal cells. In the meshes of the reticulum the 

 author has been unable to demonstrate any organized structure, 

 but the meshes sometimes present nodal points of an underlying 

 reticulum. In the fresh condition the meshes contain homogeneous 

 refractive globules which disappear on drying. 



Two series of changes may be followed in the vaccine bodies 

 in Klatsch preparations. Many of them develop basic staining 

 areas with loss of the central reticulum, and this process may con- 

 tinue until the entire body is transformed into a homogeneous 

 globule resembling mucous or colloid. In others, the reticulum 

 breaks up into granules, with or without the development of a 

 central basophile mass. 



The author has been unable at any stage, or in any derivative 

 of the vaccine body, to detect the slightest definite trace of a pro- 

 tozoon. Yet there are several hypotheses on which it may be 

 claimed that this cytoplasmic and nuclear material harbors an 

 organized virus of vaccinia : (i) The meshes of the reticulum may 

 contain a submicroscopic organism, or one which disappears on 

 drying ; (2) the vaccine body may represent a fusion of the pro- 

 toplasm of the host cell with that of the parasite, forming a myco- 

 plasm, as is claimed to exist in some diseases of plants (wheat rust) ; 

 (3) some other method of fixation and staining of isolated cells 

 may succeed in demonstrating in the meshes of the vaccine body 

 an organized structure. In any event, it must be claimed that if 

 the vaccine body contains a parasite, it is one quite different from 

 any recognized type of protozoon, or from any interpretation which 

 has yet been placed upon the structure of vaccine bodies in sections 

 of tissue. 



Besides vaccine bodies, there are other structures resembling 

 protozoa to be seen in Klatsch preparations. One of these is y 2 to 

 1 y 2 fJ. in diameter, ring-shaped and containing a chromatin granule. 



