DEPARTMENT OF EXPERIMENTAL EVOLUTION. 109 



with safety for more than 12 or 15 days. After removal the larvae 

 develop more or less pigment, although up to that time they remain 

 almost without pigment; but they do not assume the normal type 

 of pigmentation. 



Dr. Gortner and Dr. Banta attempted to modify the pigmentation 

 of the vinegar fly in the same way as that of Spelerpes. Drosophila 

 offers the advantage that the inhibitors may be placed directly into 

 the food (crushed banana) and thus gotten into the animal's diges- 

 tive tract and presumably into its tissues during all stages of its 

 active life. Some of these flies have been reared, carefully isolated, 

 through twelve generations on banana containing known percentages 

 of orcinol and resorcinol. The third generation showed marked re- 

 duction in pigment in many of the orcinol and some of the resorcinol 

 ''lines," and later generations have shown a slight further reduction. 

 The modified forms show reduction in intensity of color of the areas 

 pigmented with black pigment and a reduction in the extent of the 

 pigmented areas, particularly in the extensive black region at the 

 end of the abdomen in the male. Further breeding-tests ought to 

 show whether this is a modification produced ontogenetically in each 

 generation or one which may have hereditary significance. It has 

 not arisen through selection, as selection has been avoided in the 

 experiment. 



Reactions of Rabbits to Spores of Molds, by A. F. Blakeslee and R. A. Gortner. 



In their investigation of the main problem of the chemical nature 

 of sex, Dr. Blakeslee and Dr. Gortner have obtained results in three 

 side-problems — the effect of injection of mold spores into an animal, 

 the influence of a vegetable protein in the food upon the serum of an 

 animal, and the toxicity of expressed mold juices. 



They found that spores of Cunninghamella when injected intraven- 

 ously will kill a rabbit (four instances). Post-mortem examination 

 demonstrated the presence of germinated spores in the lungs. This 

 mold is a tropical form growing readily at rabbit temperature and 

 its growth may have caused death by mechanically interfering with 

 the functions of the organs infected. Mucor V is incapable of grow- 

 ing at body-temperature and its spores were used in a new series of 

 injections. Rabbit No. 5 received intravenously, at appropriate 

 intervals, doses averaging about 500,000,000 spores of the minus 

 ( — ) race of Mucor V. Rabbit No. 55 was similarly treated witli 

 plus {+) spores of the same species. For the twenty-fifth injection, 

 rabbits Nos. 5 and 55 received 800,000,000 spores respectively of 

 the minus ( — ) and plus (+) spores, and at the same time two control 

 rabbits previously untreated were similarly injected with like doses 

 of spores of the plus (+) and minus ( — ) sexes respectively. Separa- 

 tion cultures made from loops of blood taken from these rabbits at 



