A hormone which controls growth has been discovered by Carroll M. Williams, professor of Biology. The discovery was par of five year series of experiments which has done much toward the understanding of cancer.

Williams discussed his work last night before the Joint Session of the Federation of American Societies for Experimental Biology in Cleveland, in an address analyzing the normal growth mechanism.

Williams and his associates discovered a "growth and differentiation hormone, the role of the cytochrome system, and the relation between the two."

An understanding of the part that this hormone and the cytochrome system play in the normal growth mechanism is important Williams said, since, "Aberration in the normal growth mechanism must necessarily underlie . . . cancer.

In the address, one of three invitation lectures, Williams said he used insects rather than other animals because he "could observe in their metamorphosis events which in the other animals are usually restricted to early and frequently inaccessible stages of embryonic development."

In addition to greater accessibility, conclusions reached about the basic growth mechanisms of insects give information that applies to other forms of life, including humans, because all organisms are thought to share the same processes in growth and differentiation.

Williams discovered that growth in insects is controlled by a "growth and differentiation hormone," and that growth at any state is impossible without this compound.

The hormone is secreted by a pair of prothoracic glands in the body of the insect. In the vertebrate, this action seems, to be paralleled by the growth hormone secreted by the pituitary land.

The prothoracic glands secrete the "growth and differentiation hormone" only when stimulated by the "brain hormone" which is secreted by 26 nerve cells in the brain. This discovery led to the first step in the understanding of the growth pattern: growth in ultimately controlled in the brain.

Male Sex Cells Develop

Having discovered the prothoracic or "growth and differentiation hormone," Williams and Edmond Schmidt next devised a test for it. Then found that the presence of the hormone in a tissue culture would cause the male sex cells to develop into sperm cells.

When primitive sex cells were placed in tubes containing the blood of a growing insect, the sex cells immediately elongated and transformed into spermatoza. Blood at this stage contains the hormone.

On the other hand, when sex cells were placed in the blood of the dormant pupa--where the hormone is absent, and where the animal is not growth--the sex cells underwent no change.

This is the first test for the presence of the hormone, and it is the first instance of the production of spermatoza in tissue culture. The test also showed that growth at all stages in the life history required the "growth and differentiation hormone."

Directing the Formation