192 



Major 0. L. Williams. 



[June 14, 



at the end of this period, however, growth ceased and gradual absorption 

 occurred. 



The method adopted in this research was that of implanting subcu- 

 taneously, with aseptic precautions, several selected portions of a malignant 

 growth, freshly excised (pieces being put aside for microscopical observation), 

 and following up the changes taking place in the cells of the growth by 

 reference to sections of the implanted masses, removed for examination at 

 different periods. The time elapsing between separation from the human 

 body and the completion of implantation varied between 20 and 25 minutes. 

 Implantation was effected by puncturing the skin with a straight cataract 

 knife, and introducing on the point of the knife a piece of tissue having the 

 form of a cube of 1 — 1^ mm. The portions of tumour implanted were 

 removed at intervals of 1 — 13 days. 



The number of tumours used for implantation was 41 ; 10 tumours were, 

 however, employed in connection with unsuccessful implantations, so that 

 only 31 need be referred to here. Of these, 19 were epithelioma (17 primary 

 growths, 2 secondarily infected glands), 10 were scirrhus of the breast 

 (9 primary growths, 1 secondarily infected gland), 1 was spheroidal- celled 

 carcinoma, and 1 rodent ulcer. Implantation was made upon the monkey 

 (20 tumours), rabbit (4 tumours), pigeon and guinea-pig (each 2 tumours), 

 cat, rat, and mouse (each 1 tumour). 



The usual causes of unsuccessful experiments were suppuration and failure 

 to recover the pieces of tumour implanted. Suppuration was not met with 

 so frequently as was expected, even in the case of growths ulcerated on the 

 surface ; when present, sometimes every piece of a tumour used for 

 implantation became the seat of suppuration, in other cases suppuration 

 occurred at some of the sites of implantation, while at others no inflammatory 

 reaction occurred. A more serious difficulty was failure to recover the 

 portion of tumour implanted. In a small number of cases this arose from the 

 piece of tissue lying near the opening in the skin by which it was introduced, 

 and in consequence desiccation ensuing. In other cases the piece of tumour 

 implanted appeared to have moved from its original position and could not be 

 traced. Not unfrequently the portion of growth implanted seemed to have 

 undergone very rapid absorption, with the result that either the piece of 

 tumour implanted could not be traced or no unmistakable growth of the 

 original mass could be recognised in what is regarded as the remains of the 

 implanted mass ; difficulties of this kind were common from the fifth day 

 after implantation onwards, and thus tend to limit the number of observations 

 possible at later periods. 



The result of implantation is summarised in the table. The usual course 



