AN HEREDITARY TUMOR 513 



if there had been an abnormal growth, stimulated probably by 

 the injected substance, in which degeneration has occurred, 

 brought on by the new growth of the meal worm. 



At first I did not notice any spots in the controls, but later 

 they appeared in as great numbers in the worms that had re- 

 ceived the normal-cell suspension as in those receiving the tumor- 

 cell suspension. 



Table 2 gives the number of meal worms injected with tumor- 

 cell suspension, normal-cell suspension, and Locke's solution 

 respectively, and the number of new growths developed. Since 

 these abnormal growths occurred in the controls as well as in the 

 worms receiving the tumor-cell suspension, it is evident that they 

 are not all due to the injected tumor cells, but rather to an 

 infection. The growths resemble very much the tubercles de- 

 scribed by Adami. I tested the suspension for sterility after this 

 and isolated many of the ordinary bacteria. Of these I injected 

 fifteen-hour broth cultures of Staphylococcus and also B. subtilis 

 into meal worms. The worms receiving the Staphylococci died 

 within twenty-four hours. Those receiving B. subtilis contin- 

 ued to live and eventually developed growths like those already 

 described. Since this inoculation was done under absolutely 

 aseptic conditions — the broth having been sterile to all organisms 

 excepting B, subtilis, the pipette sterile, and the place of inocula- 

 tion on the worm kept moist with 85 per cent alcohol for ten 

 minutes — it is evident that the growth is due to an infection 

 brought on by B. subtilis. 



I have repeated the experiment of injecting tumor-cell sus- 

 pension into meal worms under absolutely aseptic conditions, 

 that is, sterilizing the fly larvae in 85 per cent alcohol, leaving 

 them in ten minutes, washing the meal worms more carefully, 

 and sterilizing the Locke's solution after each time used. The 

 suspension was tested each time for sterility, and if found not 

 sterile, the worms having received the injection were discarded. 

 Results are shown in table 3. No tumors developed in the meal 

 worms receiving the Locke's solution and normal-cell suspen- 

 sion. Of those that received the tumor-cell suspension, two 

 developed tumors and died. Seven other worms that died 



