138 



SIMPLE HISTOLOGICAL ELEMENTS. 



nor the fibres can be regarded as peculiar to cancer. Only the cells 

 and the cancer-fluid are so. But, in encephaloid cancer, the fluid is 



Fig. 76. 



Fig. 77. 



Encephaloid. Simple and compound cancer-cells. 



Melanotic cancer. (Bennett.) 



not always found. The cells alone will be here described ; and the 

 investigations of Dr. F. Donaldson, of Baltimore, will be quoted, as 

 the most explicit account hitherto given of their various forms. 1 



With a power of 555 diameters, Dr. D. found that the cells, the 

 nuclei, and the nucleoli existing in cancer are all peculiar to it. 



A. The cancer-wwcZez' (Fig. 78), whether inclosed in a cell or free, 

 are, in their form and appearance, the most constant and unva- 

 rying of all the cancer ele- 



Fig. 78. ments. They are generally 



round or ovoid in shape, 

 with a length of from 7, - 1 ^ 

 to YB^ of an inch. Their 

 contour is dark and well 

 defined, the interior con- 

 taining minute granules. 

 In width they measure 

 from -s-^-g to 2^5 of an 

 inch. It is noticeable that 

 while in other cells the 

 nucleus is generally found 

 near the centre, in cancer 

 no rule in this respect is 

 observed. Two or more 

 nuclei, with their nucleoli, 

 both of great size in pro- 

 portion to the diameter of 



' ' j^ '* ' fir^ 



?V' v j 



Cancer nuclei, a. Type form. b. The same, with a piece 

 nicked out of the side accidentally, c. Shows a free nu- 

 cleus in which the molecular granules are very minute, 

 often met with in perfectly fresh specimens, d. A nucleus 

 in which larger granules have commenced to form. e. The 

 characteristic nucleolus, with its dark contour and bright 

 centre, h. Fine molecular granules, i. The second va- 

 riety of granules, or gray granulations, j. Fat-granules. 



American Journal of the Medical Sciences, vol. xxv. p. 43. 



