CARCINOMA AND SARCOMA 317 



being a weakness, is a strong point in this classification. We 

 have, that is, to recognize that among these Mesolepidomata, 

 as above defined, we meet with several forms of tumours of 

 transitional type, tumours which in their least aberrant portions 

 show characters which approximate them to the Carcinomata, 

 and in their more aberrant portions are indistinguishable from 

 Sarcomata. And, indeed, it is only by a study of the embryogeny 

 of the tissues from which these tumours are derived that we gain 

 any satisfactory comprehension of the why and wherefore of 

 these peculiar characters. 



Here let me point out that, employing the terms here intro- 

 duced, based as they are upon the embryogeny of the different 

 tissues and the tumours derived from them, we may allow the 

 terms " carcinoma " and " sarcoma " to revert to their earlier 

 and purely histological significance. And I would emphasize 

 that it must not be understood that these terms, carcinoma 

 and sarcoma, are to be regarded, and are by me regarded, as being 

 synonymous with " atypical lepidoma " and " atypical hyloma " 

 respectively. Rather, I would lay down that, accepting this 

 nomenclature, we may safely speak of any tumour of the aberrant 

 glandular type as carcinoma, whether it be of epiblastic or 

 mesothelial origin, and any tumour of aberrant and so-called 

 embryonic connective tissue type as sarcoma, whether derived 

 from the mesenchyme, the epiblast (e.g. gliosarcoma), or even 

 from the endothelium or mesothelium. 



Of late years there has been an ineffectual attempt to restrict 

 these two terms. Thus, many authorities have refused to speak 

 of malignant adenomata of the kidney and suprarenal as being 

 true carcinomata, and others have strenuously opposed the 

 employment of the term gliosarcoma. Nevertheless, the same 

 authorities, while refusing to speak of a cancer or carcinoma 

 of the kidney, freely refer to carcinoma of the uterus, although, 

 like the renal tubules and the suprarenal, the uterine mucosa is 

 of mesothelial origin. In short, it has been proved impossible 

 to employ these terms with embryogenetic limitations, and this 

 introduction of a nomenclature which is based upon embryogeny 

 ought, if accepted, to permit us to use them, as they ought to 

 be used, in the purely histological sense. 



It will be seen that I in no sense urge that (were it possible !) 

 the use of these terms (sarcoma and carcinoma) be done away 



