144 SIMPLE HISTOLOGICAL ELEMENTS. 



site would rely upon it alone. The following is believed to be the 

 only tenable view of this subject : 



1. In all cases of well-developed cancerous formation, the micro- 

 scope, in the hands of one skilled in its use, will alone demonstrate 

 the true character of the growth, unaided by any knowledge of its 

 appearance to the naked eye, of its tactile properties, or of the his- 

 tory of the case. This it will do by detecting one or more of the 

 peculiar forms of cell or nucleus already described. Here, therefore, 

 the diagnosis may be positively expressed in the affirmative. 



2. But there are all possible grades of development, from the en- 

 cephaloid, as the most strongly pronounced form of cancer, to the 

 fibrous cancer, and onward to the simple, innocent sarcoma. There 

 will, therefore, be a corresponding shading-off of the peculiarities 

 of the minute cancer elements (cells, nuclei, &c.) into the normal 

 elements of the tissues. Besides, when cancer-cells are still young, 

 they do not present the peculiarities before mentioned. 1 



In the imperfect or early development of cancer, therefore, the 

 cancer-cell may so nearly resemble the fibro-plastic or some other 

 cell, that a microscopic discrimination is impossible. Here, then, 

 the microscopic diagnosis must be guarded, and the history of the 

 case and the other sensible properties of the growth must decide. 



3. The cancer elements may exist in small amount in a mass sup- 

 posed to be cancerous, and in the midst of a variety of other minute 

 elements, and therefore escape detection. If so, the microscopic 

 diagnosis is wferentially negative, but not unqualifiedly so. The 

 unaided eye, the sense of touch, and the history of the case may, 

 however, together, decide the diagnosis unqualifiedly, either in the 

 affirmative or the negative. 



4. In cases of well-developed cancer, therefore, the microscope, 

 since it alone may decide the diagnosis, is in the highest degree 

 reliable. In the other two cases mentioned, it is less reliable than 

 the other means alluded to; but here, also, it may prove of the 

 highest value, by confirming or opposing the diagnosis suggested 

 by them. It is the absurd assumption that the microscope can de- 

 cide in every possible case, which has brought the instrument into 

 disrepute. It merely enables us to see what would be invisible 

 without it ; and gives, so far as the minute elements are concerned, 

 an advantage over those who refuse to use it, like that which one 

 who has perfect sight enjoys in respect to things visible to the 

 naked eye, as compared with the purblind. But as the unaided 

 sight alone is almost never expected to decide, in case of suspected 

 cancer, without regard to the tactile properties and the history of the 

 case; so the sight, when aided by the microscope for it is mere 

 sight still must not, except in a single class of cases, be relied 

 upon alone. In these it should be recognized as an arbiter in the 

 diagnosis of cancer; in all other cases it is merely a valuable aid. 



1 All pathological newly-formed cells have no especial character peculiar to them. 

 (Wedl, p. 66.) 



