2^0 IOC A I, riSSlE RF.ACriVITY 



()l Mouse \ sliowcd ;i t^iadiial icurcssion lo ahoiil onc-tfiuli ol llic s^iowth 

 picscni Ixloic the liisi injcciioii. Allci llic lomili iujcHtioii the growth re- 

 ;i|)|)e;iit(l. In Mice \l ;iii(l \ll ihe luinois completely icgiessed on the fourth 

 week allei lunioi inoculation ;uicl no growth was evident later. 



(.)()iij> 1/(1. (i'Oiu mice.) Alice XIII-XVI received intraperitoneal injections 

 of 0.5 c.c. of filtrate No. 1700 on the eighteenth clay of tumor growth. Mouse 

 XIV died twenty-tour hoius latei. Jt showed extensive hemorrhage in the 

 iinnor mass. Mice XIII and XV received in addition similar injections on 

 the twentieth and twenty-third days, and Mouse XVI on the twentieth, 

 twenty-third, and thirtieth days (A tumor growth. The tumor ot Mouse XIII 

 regressed to about one-eighth ol the size before the first injection. The third 

 injection killed the mouse. The autopsy showed a large necrotic mass with 

 doubtfully active growth. Mouse XV, dead on the thirty-seventh day of tumcjr 

 inocidation, was foinid at autopsy free of growth. The tumor of Mouse XVI 

 regressed to one-sixth of the size before the first injection and reappeared 

 later. 



(iyoiij) III. In this group 15 mice bearing seventeen day old tumcjrs were 

 each injected intra\enously with 0.5 c.c. of filtrate No. 1700. Three mice 

 died twent)-four hours later. They showed hemorrhagic necrosis of the 

 tumors. Within the follo^ving t^vo weeks there was observed cfjniplete re- 

 gression of the tumor growth in 10 mice. Three of these mice appeared com- 

 pletely free of tumors on the third \veek, while in 7 of these mice the growth 

 began again. In 2 mice the gro^vth was uninfluenced at any time after 

 inoculation. 



Contiol groups. Nineteen mice in all were set aside as controls, a few for 

 each experimental group. They all dexeloped large tumors, which showed 

 no spontaneous regression at any time. Two of these mice were injected in- 

 tra\enously each with 0.5 c.c. of 2 per cent glucose broth containing 0.4 

 per cent phenol. Ihere appeared to l)e no effect on the development of 

 the tumor. 



It ^vas concluded from the above experiments that the injec- 

 tions of the meningococcus Group III '"agar ^vashings" filtrates 

 Avere highly toxic and killed a large number of mice. Once the 

 mice recovered, however, from the immediate effect, they re- 

 mained in a good general condition. The repeated intravenous 

 injections of 0.5 c.c. of the filtrates employed at the time were 

 most destructive for the tumors. Next, in effectiveness ^vere re- 

 peated intravenous injections of 0.25 c.c. and repeated intraperi- 

 toneal injections of 0.5 c.c. of the filtrate. Repeated intraperi- 

 toneal injections of 0.25 c.c. remained ^vithout effect. 



In later experiments, hcnvever, a single intravenous injection 

 of a potent preparation was sufficient to produce a rather drama- 

 tic effect upon the tumors. The gross and microscopic effects of 

 the active principles upon the tumor are illustrated in the photo- 

 graphs. As is seen, the tumor becomes severely hemorihagic lour 



