2436 Journal of Applied Microscopy 



Some circulation must be maintained of the blood, lymph or diffusion stream, 

 although it need not be complete, or fatty metamorphosis will not occur. 



The most essential condition for the appearance of fat is the life of the cell. 

 Dead cells do not undergo fatty change. Without doubt the presence of fat 

 within the cell can be due to a great variety of conditions. 



The experiments summarized in this study add no support to the view that 

 fat can originate from the cell proteids. j. h. p. 



^ ., ,. ... J „.,.«, Ti In the epithelial cells of the skin in 



Councilman, Inagrath and Brinckerhoff. A Pre- 

 liminary Communication on the Etiology of smallpox the writers have discovered 

 Variola. Jour, of Med. Research, 9 : 372- peculiar bodies which they regard as 

 375, 1903. . . . JO 



livmg organisms and the cause of the 



disease. Two cycles of development are described. The primary or intracellu- 

 lar cycle of the parasite occurs in vaccinia as well as in variola, but the second 

 or intramiclear cycle, which is possibly sexual in character, takes place only in 

 variola. The intranuclear development was also demonstrated in the monkey, 

 and this is the only animal in which variolous lesions can be produced. 



The first stage of the intracellular cycle was observed by Guarnieri in 1892, but 

 the bodies he described have been regarded by many authorities as degeneration 

 products. They were small structureless bodies from one to four microns in size. 

 The writers found them in the lower layers of the cutaneous epithelium before 

 vesicles had formed. The bodies increased in size, granules appeared and the 

 vacuole which surrounded each parasite enlarged until a central space about the 

 nucleus of the epithelial cell was formed. The larger bodies may exceed the 

 size of the nucleus of the epithelial cell. They have an irregular contour and 

 resemble amceb?e. No definite nucleus is demonstrable within the bodies. Seg- 

 mentation of the parasite occurs with the formation of round spore-like structures 

 about one micron in size. 



Coincident with the segmentation and disappearance of the intracellular forms, 

 small ring-like bodies appear in the nuclei of the epithelial cells. These intra- 

 nviclear organisms enlarge and consist of a circle of spherules which sur- 

 round a large central vacuole. After further development segmentation occurs. 

 The cell containing the parasite undergoes complete degeneration. The spores 

 formed by the intranuclear organism are considered by the writers as the true 

 infecting material of variola. They are made out with difficulty and were first 

 seen in a photograph of the tissue. By the time young vesicles have formed the 

 development of the parasite is completed and only spores are present in the later 

 lesions of the disease. j, h. p. 



