This volume summarizes present concepts of the regulation and mode of action of thyroid hormones in 18 papers of international origin. There is supplementing discussion of each paper, and there are three general discussions, which provide invaluable perspective and criticism. Although not a clinical volume, it belongs in the library of all whose interest in clinical thyroid physiology is more than casual.
The first eight papers take up hypothalamus-pituitary-thyroid relationships with respect to TSH, iodine metabolism, and thyroid hormone synthesis. Brown-Grant provides an intriguing feed-back hypothesis which assigns to the hypothalamus the role of regulating the content of thyroxin in the blood reaching the anterior pituitary.
The second half of the colloquium is devoted chiefly to the search for the elusive peripherally active forms of thyroid hormones. Mme. Thibault presents provocative evidence that thyroid hormones may be transformed by tissues into several "active derivatives, each of them being specific of