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ON A CHARACTERISTIC ORGANISM ASSOCIATED 
WITH CANCER OF THE BREAST 
By KEITH W. MONSARRAT, F.R.C.S.E. 
SURGEON TO THE NORTHERN HOSPITAL, LIVERPOOL 
IN this paper an account is given of certain researches, part of a series conducted 
during the last five years on the subject of carcinoma. These researches have 
been confined to one clinical type of cancer, that affecting the female breast. 
Although it is possible that the cause of cancer is universally one and the same, 
arguments to the contrary can be adduced, and research is simplified by narrowing 
its limits. The following are the subdivisions of the paper : — 
1. Previously reported research. 
2. The method of examining the growths. 
3. The morphology of the organism isolated. 
4. The histology of the growths examined and the culture results obtained 
from each. 
5. Commentary. 
I. PREVIOUSLY REPORTED RESEARCH 
In a paper read before the Royal Society on December 14, 1899, an accou 'it 
was given of certain organisms isolated from carcinomata of the breast and uterus. 
They were classed as blastomycetes. They were isolated on glucose agar ; other 
media were employed, but growth occurred on the glucose agar medium alone. 
Subcultures were obtained on wort agar and potato, and in wort bouillon and 
neutral bouillon, and their characteristics described. A special method of staining 
the organism in the tissues was described, and its morphological characters 
summarized as follows : — ' Fresh specimens trom cultures are spherical, from four 
to ten microns in diameter, and in most cases take an aniline chromatin stain 
diffusely. There is, however, a great variety in the distribution of the chromatin ; 
it is sometimes aggregated to one pole, sometimes divided up at different parts 
of the cell, and in other cases it is represented by a few isolated granules. The 
capsule is delicate. Multiplication in cultures takes place by budding. 
' In the primary growths produced by intraperitoneal inoculation of the 
organism, the latter is also in most cases spherical, possesses a delicate capsule, 
