REACTIVITY OF MALIGNANT NEOPLASMS 2^5 



pressed by the extensi\e hemorrhagic condition accompanying 

 this phenomenon, ^vliich in most cases could be observed ex- 

 ternally throiigii tiie skin. When conspicuotis, the reaction was 

 detected by him as early as one hour alter the injection ol the 

 bacterial filtrate. 



Negatively reacting tumors: 



This groii)) consisted of 69 mice and rats bearing: 



1. Comparatively slo^vly growing spontaneous or transplantable 

 malignant tumors Avhich rarely or never regress; 2. Rapidly grow- 

 ing malignant tiunors ^vhich eventually regress (heterologous 

 grafts) ; and ^^. Benign embryomas or grantdomas, ra])idly de\'elop- 

 insf, Aviiich e\entuallv regress. 



In a recent ]Hd)lication, Duran-Rcynals (1935) expresses the 

 opinion that the jjjienomenon in the tinnor is conditioned by two 

 sets of factors: the intrinsic factor depending on the sensitivity of 

 the tiunor itself: and the extrinsic one depending on the activity, 

 quantity, and roiue of inocidation of the active principles. The 

 variotis stisceptible tumors recjuired smaller doses of active prin- 

 ciples to produce the same effect and the same restdt was also 

 obtained ^vith fdtrates of low toxicity as with mtich more active 

 filtrates. Also, the roiue of inoculation did not seem to be a 

 matter of mtich importance. Inasmtich as in his preliminary ex- 

 periments the slowly grooving spontaneous carcinomas of mice 

 were found practically non-susceptible, many attempts Avere made 

 by Dtnan-Reynals to determine whether filtrates of high potency 

 could overcome this apparent resistance. Accordingly, a series of 

 tests were carried out on 52 mice bearing mammary carcinomas 

 and using highly potent B. typhosus "agar washings" filtrates (sup- 

 plied by me) and filtrates of six day old broth cultiue of B. 

 enteritidis and mouse typhoid. The malignant character of the 

 ttmiors Avas histologically confirmed in every case either by biopsy 

 or by postmortem examination. 



The grotip of mice iKuing larger timiors and recei\ing the 

 larger dose of acti\e principles had a higher incidence and greater 

 intensity of local reaction, higher early mortality, and lower per- 

 centage of partial or total inhibition than did the group ^vith the 

 preponderance of small tumors, receiving the smaller doses of 

 acti\e ])i"incij)les. 



Inhibition \vas better obserxed xvhen small or medium sized 

 timiors were treated wiiii small doses of acti\e jjrinciples. The 



