676 APPENDIX. 



The cancer-cells maybe demonstrated in the thick, opaque juice 

 which exudes from the freshly-cut surface of a cancerous tumor, 

 while the relation of the constituent elements of the mass are 

 best shown upon a thin section, made with a Valentin's knife. 

 The fluid portions containing the cells will be found, in the are- 

 olae or interspaces formed by the crossing of the fibres. Both the 

 fibres and cells vary much in appearance in different specimens. 

 Sometimes the cells are round, sometimes elongated into fibres, 

 and occasionally they present very irregular forms. The nuclei 

 also diifer considerably in numbers and size. 



Dr. Walshe divides cancerous tumors into three varieties, 

 according as the viscous juice, fibrous, or cellular elements pre- 

 dominate. 



Very great difficulty is often experienced in arriving at an 

 accurate opinion as to the cancerous or non-cancerous nature of 

 a tumor ; because there is no single element which can be re- 

 garded as pathognomonic of true cancer. " iSTeither the cha- 

 racter of the cells," says Dr. Beale, " nor the nature of the 

 matrix, nor the arrangement of the elementary constituents, can 

 separately determine the point, and it is only by carefully noting 

 the collective appearances observed upon a microscopic exami- 

 nation that we shall be enabled to decide." 



Enchondroma, epithelioma, certain fibrous tumors containing 

 spindle-shaped cells, &c., resemble true cancer so strongly that 

 they have been called cancroid growths. For the peculiarities 

 of each of these varieties of tumor, the student is referred to 

 the works of Lebert, Bennett, Walshe, and other writers upon 

 this subject. In the following table, taken from Dr. Lionel 

 Beale's work on the medical applications of the microscope, will 

 be found enumerated the most important characters which dis- 

 tinguish the true cancer-cells from those of cancroid tumors. 



Cancerous. CancroiiJ. 



Cells not connected with the matrix Cells connected with the matrix, often 



in a regular manner, or forming lamina;. forming distinct laminfc. 



Cells differing much from each other Cells resembling each other in size 



in size and form. and general outline. 



Cells readily separable from each other. Cells often cohering by their edges, 



Cells not connected together at their which generally form straight lines, three 



margins, their edges seldom forming or four cells being frequently found 



straight lines. united together. 



Cells containing several smaller cells Cells usually containing one nucleus, 

 in their interior often met with. 



Nuclei varying much in size and num- Nuclei not varying much in size in 



ber in different cells. different cells. 



Juice scraped from the cut surface Juice scraped from the cut surface, 



containing many cells floating freely in containing small collections of cells, 



the fluid, and not connected with each which are often connected with each 



other. other. 



Dr. Donaldson' asserts positively that true cancer can be dis- 



' American Journal of Medical Sciences, January, 1853. 



