1. The foreign materials used did not produce an increased growth in length in any of the animals. Instead, a marked shortening often resulted.
2. This series of experiments does not warrant the clinical or surgical use of foreign materials in the epiphyseal cartilage plate region to promote the length-growth of bones.
3. These experiments afford an interesting study of the reaction of young, growing bone cells to various foreign materials; and give a relative idea of their toxicity, or cell reaction of bone to a wide range of materials. Some of these are mentioned in the literature. The reaction of bone to metals has been worked out by Zierold and others. One finds little mention of woods. They seem to be quite innocuous to the bone cells and apparently interfere but little, if any, with the normal growth processes. Apparently they tend to stimulate bone-shell formation about themselves. More experimental work, with a view to their possible use in bone surgery, should be done.