A Benign Tumor in Drosophila. 



5i 



acid. Sulfates are precipitated with barium chloride and the 

 nitrate is made ammoniacal, then acid with acetic acid and phos- 

 phates are precipitated with ferric chloride. The precipitate is 

 dissolved in nitric acid and the phosphoric acid is precipitated 

 with ammonium molybdate and the yellow precipitate is titrated. 

 The filtrate from the ferric acetate precipitate is treated with 

 sulphuric acid to remove the barium and with hydrogen sulfide 

 to remove the copper and the filtrate is evaporated to small 

 volume. Calcium is precipitated in a centrifuge tube as oxalate, 

 washed and titrated. The supernatant liquid and washings are 

 evaporated, heated to remove ammonium salts and the magnesium 

 is precipitated in a centrifuge tube as magnesium ammonium 

 arsenate. This is washed and then dried, in vacuo, over sulfuric 

 acid. It is dissolved in acid, transferred to a distillation flask and 

 the ammonia determined by distillation and Nesslerization. The 

 supernatant liquid and washings are treated with hydrochloric 

 and hydrobromic acids, evaporated to dryness, freed of ammonium 

 salts and arsenic, sulfuric acid is added and the potassium and 

 sodium are weighed as mixed sulfates in a platinum dish. Potas- 

 sium is then precipitated as the cobaltinitrite and weighed. 1 



30 (1490) 



A benign tumor in Drosophila. 



By Mary B. Stark, (by invitation). 



[From the Zoology Laboratory, Indiana University.] 



In a strain of flies with a lethal tumor, i.e., a tumor occurring 

 in one half of the males and causing their death, another tumor 

 has appeared as a mutation. The new tumor differs from the 

 lethal one in that it is not sex-linked, i.e., it appears in females as 

 well as males, and further in that it does not cause the death of 

 the flies in which it occurs. Linkage experiments show that one 

 at least of the genes essentially for tumor development is in the 

 third chromosome closely linked to dichaete. 



Garola and Braun, Annales de falsifications, 10, 572, 1917. 



