The writers examined every day the specific gravity of the blood of silkworms from the beginning of the 2nd stage of larvae to the last day of moths by means of the copper sulphate method of R. A. Phillips et al. The results obtained are as follows:
1) It is certified that the tendency of rise and fall of the specific gravity of the blood is about the same in every one of the 2 nd-5 th stages; namely, the specific gravity of the blood rises rapidly until the voraceous period after a little descent at first, and then falls again until the setting in molt or the spinning period.
2) In the pupal stage the specific gravity of the blood descends gradually though sometimes it rises a little at the beginning, and falls rapidly at the end.
3) The specific gravity of the blood of moths ascends speedily about first 3 days and then descends slowly to the death. The writers explained these changes of specific gravity as follows:
4) At the beginning of each larval stage, the nutriment in the blood is consumed by the restoration of molting period and so the specific gravity descends.