197 



The Nature of the Immune Reaction to Transplanted Cancer in 

 the Rat. 

 By Wm. H. Woglom, M.D. 



(Communicated by Sir J. R. Bradford, Sec. R.S. Received March 15, — Read 

 May 2, 1912.) 



The purpose of the present paper is to extend to another species the 

 investigation of the early history of tumour grafts carried out by Russell* in 

 normal and immune mice, and to describe in detail the reactions taking 

 place in and about fragments of the Flexner-Joblingt adeno-carcinoma of the 

 rat after its transplantation into normal and resistant animals. 



Immune rats were obtained by selecting those which had proved them- 

 selves resistant to one or two inoculations of the tumour in question, or by 

 subjecting animals to previous treatment with 02 — 0%3 c.c. of an emulsion of 

 rat embryo skin, and the introduction of the grafts destined to be excised for 

 the study of early stages took place in all cases two or three weeks after the 

 last immunising treatment. 



Fragments removed after 24 hours show commencing degeneration of the 

 stroma and of the parenchymal elements toward the central parts, while the 

 tumour cells at the periphery have, on the contrary, preserved their vitality. 

 There is no visible difference at this time between grafts removed from 

 immune rats and those from normal animals. 



The most interesting epoch in the history of a tumour nodule which is 

 establishing itself in a new soil is the third day. In the majority of 

 fragments removed from normal rats at this period the fibrinous exudate and 

 the cleft, both formerly separating the graft from its host, have disappeared. 

 The fibroblasts of the surrounding connective tissue have entered into the 

 growth, and are engaged in the building of a new stroma, while penetrating 

 capillaries can be discovered at the edge of the young tumour. The outer- 

 most cells of the parenchyma are in active mitosis, but the centre of the 

 graft is quite necrotic. In fig. 1, representing the edge of a nodule which was 

 removed 70 hours after implantation, the close connection between the growth 

 and its host can be readily appreciated from the intimate commingling of 

 tumour cells and connective tissue elements, as they are reproduced in the 

 drawing. A new capillary, containing blood, has entered well into the fragment, 



* Russell, B. E. G., ' Third Scientific Eeport, Imperial Cancer Eesearch Fund, London,' 

 1908, p. 341. 



t Flexner and Jobling, 'Monographs on Medical and Allied Subjects, Rockefeller 

 Institute,' New York, 1910, No. 1, p. 1. 



