The Life Cycles of Trichogramma Minutum in Relation to Temperature.

5 to 10 days. At the end of that time it was noticed that in every case the plants containing the liver extract in solution were distinctly greener than the controls without the liver extract. Some factor in the liver extract has apparently checked the destruction of the chlorophyll; this destruction of chlorophyll goes on constantly, but in the daylight the pigment is constructed as fast as it is destroyed. Whether this is -the same effect as observed in the use of liver extract in cases of hemoglobin deficiency, such preliminary experiments can not decide. Purified extract or amino acid crystals from liver extraet should be used instead of the crude extract. Also it should be of interest to see if the liver extract will aid in the formation of chlorophyll in seedlings completely etiolated. Miss Mary E. Reid (unpublished experiments) found that albino seedlings when fed liver extract in a similar fashion showed a greening in excess of controls. Since laymen still like to get evidence upon the fundamental relationship of plants and animals, such experiments might be brought forward in support of the doctrine of the common origin of plants and animals, but such was not the original purpose of these rather elementary researches. On the other hand, these experiments as here reported were simply meant to be suggestive of the aid which the study of plant physiology may be able to render to the study of animal physiology on the assumption that vegetable and animal substances of a similar chemical nature and of common origin may be supposed to have a physiology at least similar if not strictly identical.