Effects of feeding silkworms on extract of the anterior lobe of the pituitary gland.

Silk worms have been fed upon extract of the anterior lobe of the pituitary gland, special precautions being taken to ensure that the insects actually ingest the active principle.Marked retardation of growth is described. Metamorphosis was delayed likewise, and the mortality at the various metamorphological stages much greater than in the control group of worms.Normal movements were unaffected but definite slowing of the circulation was observed.Reasons are advanced for the belief that the retardatory effect was caused by a failure of metabolism, and it is suggested that this may relate to carbohydrate metabolism in particular. A distinction between vertebrates and invertebrates is noted, the former exhibiting an initial retardatory effect followed by an acceleration of growth whilst the latter only show retardation.