TUMORS. 295 



feebleness, anaemia, and that general impairment of the nutritive func- 

 tions of the body known as cachexia. This condition is frequently ren- 

 dered worse by the mental status of the patient in the presence of such 

 a traditional object of alarm. 



It should be remembered, however, that so long as they are localized 

 and have not undergone degenerative changes, even the most malignant 

 tumors do not usually give rise to a cachexia, since the drain upon gen- 

 eral nutrition by their simple growth is not, under ordinary conditions, 

 very great. When the system is deteriorated by the absorption of septic 

 materials from tissue degeneration, however, this may become a very 

 important factor. 



This condition of cachexia, so evidently secondary to the growth and 

 degeneration of the tumor, was formerly termed a dyscrasia or diathesis, 

 and was supposed to precede and induce the growth of malignant tumors, 

 particularly cancers. 



It is further to be noted that the fragments of tumors which have 

 found access to the vessels may act as simple emboli leading to immediate 

 death, or, if infected, may incite nietastatic abscesses. 



It was formerly supposed that the cells of malignant tumors, particu- 

 larly of careiuomata, had a characteristic structure and appearance, and 

 that by the examination of single or of a few separated cells the nature 

 of the tumor could be determined. From the above considerations it 

 will be evident, since all tumor cells have their prototypes in the normal 

 body, that there is nothing pathognoinonic in the appearances of single 

 cells. It is by a study of the general structure and of the topography 

 of tumors, as well as of the characters of the individual cells, that we are 

 enabled to determine their nature. And even then we must often bring 

 to our aid the clinical history and gross appearances of the growth be- 

 fore a definite conclusion can be reached. We may indeed sometimes, 

 aided by the clinical history or gross appearances, be able, by the micro- 

 scopical examination of scrapings from a tumor or of fluids from an 

 internal cavity in which it is growing, to form a reasonable conjecture 

 regarding its nature. As a rule, the peripheral portions of the more 

 rapidly growing tumors are best adapted for microscopical examination, 

 because here secondary degenerative changes are less likely to have oc- 

 curred than in the central parts. 



The Transplantation of Tumors. In view of the frequency with which 

 fresh foci of tumor cell growth are established in the same individual by 

 metastasis, by transplantation over serous surfaces, or on apposed mucous 

 membranes, and stimulated by the few recorded cases in which tumors 

 seem to have been incited in another individual through transference of 

 the cells by contact, it is not surprising that a great deal of experimental 

 work has been done upon the artificial transference of tumors by various 

 forms of grafts or transplantations from man to the lower animals and 

 from animal to animal both within and without the limits of species. 



The scope of this work does not permit a review of these interesting 

 researches. But it may be said in general that they have been almost 



