276 THE INFECTIOUS DISEASES 



other parts of the epithelial cytoplasm. They are frequently surrounded 

 by a clear space, which may become of considerable size. They have 

 not been found in the nucleus. 



Hand-iu-haud with the increase of these bodies there are progressive 

 degenerative processes in the epithelium of the inoculated region, with 

 the formation of various structures characteristic of the degeneration of 

 protoplasm under a great variety of conditions. 



While many observers following Guarnieri have felt justified, largely 

 on morphological evidence, in the belief that the vaccine bodies are pro- 

 tozoa, others have been led to the conclusion that many if not all the 

 appearances presented can be accounted for by protoplasmic degenera- 

 tions induced by other agencies. Several experimenters, indeed, by the 

 introduction into the rabbit's cornea of chemical and other substances 

 not at all related to the vaccine virus, have been able to induce degenera- 

 tive protoplasmic structures resembling the vaccine bodies. l 



It is evident that the proof on morphological grounds alone of the 

 protozoan nature of such minute structures is a task of extreme difficulty, 

 associated as they frequently are with the readily stained products of 

 protoplasmic degeneration. 



In April, 1903, Councilman announced the results of a long series of 

 studies by himself and his associates, Magrath, Briukerhoff, and Tyzzer, 

 on the excitant of smallpox. * The observations of Guaruieri, Wasielewski, 

 and others, on the vaccine body, were in the main confirmed. These 

 observers find the vaccine bodies in the lower layers of skin epithelium 

 before the production of the vesicles and in the advancing edges of the 

 young vesicles. They find morphological evidence of the segmentation 

 of the bodies and the formation of round, spore-like structures about one 

 micron in diameter. Councilman further announced the discovery of 

 other bodies, not before described, within the nucleus of the epithelial 

 cells in the infected region in man. These intranuclear structures are 

 circular, ring-like, with a central dot, and may be seen singly or in clusters. 

 They are from one to one and one-half microns in diameter. These intra- 

 nuclear bodies Councilman regards as a further stage and as representing 

 a second complex cycle of development of the smallpox parasite. The 

 intranuclear structures he believes to be developed from the spore-like 

 bodies resulting from the segmentation of the iutracellular vaccine body 

 which penetrate the nucleus. Councilman finds the vaccine bodies both 

 in the epithelial cells of the smallpox lesion in man and in the lesion in- 

 duced by vaccination of the rabbit and calf. But the intranuclear forms 

 have not been found in the latter animals. After inoculation of the 

 monkey with the contents of smallpox pustules, both the iutracellular 

 and the intranuclear forms were found. He believes it to be probable 

 that in smallpox the parasite undergoes complete development, passing 

 through two cycles, an iutracellular and an intranuclear, while in vaccinia 

 only one, the primary, cycle is achieved. 



'See Huckel, Ziegler's Beitr., Suppl. Heft, 1898; also Busing, Traus. N. Y. Path. 

 Soc., January, 1904. 



2 "Studies on the Pathology and on the Etiology of Variola and Vaccinia," Jour, of 

 Med. Res., vol. xi., 1904. 



