CHARACTERISTIC ORGANISM ASSOCIATED WITH CANCER 
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serum, human serum with "2 per cent, glucose, and a medium prepared from car- 
cinoma material with 2 per cent, peptone added. 
In three or the tour cases in which positive results were obtained, I used 
glucose broth, glucose agar, and milk alone. In one case, the organism developed 
in ordinary nutrient broth. These are the only media in which growth occurred. 
III. THE MORPHOLOGY OF THE ORGANISM ISOLATED. 
The following description is based upon the study or the organism (a) in 
the primary cultures obtained from the tumours, and in subcultures from these, 
(/>) in the cultures obtained from the lesions produced in animals, and in sub- 
cultures from these. 
In the chapter which follows this, I shall describe in what way, and by the use 
of what methods the various types of the organism have been found associated with 
the several growths and animal lesions. 
For the sake of clearness in description, the forms under which the organism 
occurs in cultures are here divided into two main types, A and B. These types are 
directly related, and are merely two phases in the life history of the organism. Their 
separation is artificial, and based only on morphological grounds. It is also tor the 
sake of clearness and simplicity in description that I first take type A, a form of the 
organism which does not appear in the cultures isolated in the first instance from the 
tumours, and secondly, describe type B, which is the form which occurs in these 
cultures. 
The following is the order of description :— 
1 . The morphology of type A. 
2. The method of reproduction of type A. 
3. The morphology and development of type B. 
4. The macroscopic appearances of the cultures. 
1. The Morphology of Type A 
The following description is derived entirely from fresh undried specimens, 
unmounted. Cultures on solid media are prepared by placing a drop of water on 
the slide, giving this a slight tinge with the stain employed, and placing in the 
drop a particle of the culture. In the case of fluid cultures, a loopful is taken and 
lightly coloured. A cover glass is then placed on the drop, and the specimen 
examined immediately. Drieti preparations give in most cases what have been 
ascertained to be quite unnatural appearances, and to some of these reference will be 
made later. 
(</) Shape. Living specimens are spherical, oval, and lemon-shaped ; in old 
cultures are found crenated forms and other irregular types. Actively-growing 
forms in young cultures are all spherical. 
