ABSTRACT
It has been frequently stated that many species of flies, including houseflies and blowflies, can be kept alive and healthy on a diet consisting only of cane sugar and water; on this they are able to live for the maximum length of time, which, in the case of the blowfly Calliphora erythrocephala, is about 2 months at 27° C. Addition of protein is essential only for the development of the eggs, as it does not increase the duration of life and there is, indeed, evidence that it may have the contrary effect. Flies thus represent an excellent medium for studying problems of carbohydrate metabolism, and the present investigation deals particularly with two questions: what effect have substances other than cane sugar on the length of life of the fly, and to what extent does the presence and absence of enzymes in the gut account for the utilization or non-utilization of these various substances?
