488 Drs. Russ aud Chambers. Action of Radium [Mar. 14, 



Control Grafts. 



The day after inoculation the tissue of the graft is almost entirely 

 necrotic, only those sarcoma cells at the edge look in good condition. 

 There is extensive invasion of the graft with leucocytes and much inflamma- 

 tory oedema of the surrounding tissue. On the second day active 

 proliferation of the sarcoma cells at the periphery is evident, and they 

 soon form an encircling ring of growth around the graft. Sarcoma cells 

 extend outwards into the connective tissue and also invade the central 

 necrotic area. By the 6th and 7th day the mass is completely solid and 

 has the structure of the fully developed tumour (vide microphotograph 2). 



Irradiation for 24 Hours. 



On the day after inoculation the graft, as in the control, is almost entirely 

 necrotic. The inflammatory changes and cedema set up in the surrounding 

 tissue are less marked ; there is also less invasion with leucocytes, and 

 the sarcoma cells are all apparently degenerate. On the third day they 

 can still be detected, but they show no signs of proliferation. On the 

 fourth day the sarcoma cells have completely disappeared. The graft now 

 consists of granular structureless material, a few leucocytes and nuclei 

 alone being left (vide microphotograph 3). There is commencing vascularisa- 

 tion and fibrous tissue formation at the periphery. 



Irradiation for 80 Minutes. 



On the day after inoculation the reaction of the surrounding tissue to the 

 implanted graft is again less marked than for the controls, and the graft is 

 largely necrotic. Sarcoma cells in good condition can, however, be found at 

 the edge. By the sixth day the graft is almost completely vascularised and 

 many of the sarcoma cells at the edge appear to have proliferated to a slight 

 extent. The condition shows (vide microphotograph 4), a distinct contrast 

 with the preceding. At a later stage the graft is largely replaced by fibrous 

 tissue but the sections can be distinguished from those of the 24-hour 

 irradiation series by the presence of a few large sarcoma-like cells embedded 

 in the fibrous tissue. 



Irradiation for 20 Minutes. 



Both the experimental and control grafts formed tumours, the former being 

 the smaller. 



The sections of the experimental grafts are similar to the controls 

 throughout this series, except that in the former the rate of proliferation of 

 the cells is delayed. Moreover 11 days after inoculation the irradiated 



