A RETICULOCYTOGENIC AGENT FOR GUINEA-PIGS PRESENT IN CERTAIN GASTRO-INTESTINAL SECRETIONS

¹ Sir William Dunn School of Pathology, Oxford

1. A reticulocytogenic agent for reactive guinea-pigs (selected according to a modified Jacobson technique) is found in the pyloric, duodenal and ileal secretions of the pig, in the pyloric and duodenal secretions of the cat and in the duodenal secretions of the rabbit and goat, but not in the fundic secretions of either pig or cat.

2. The sites of the production of the agent, therefore, correspond to those sections of the gastro-intestinal mucosa which have been found by Meulengracht and his co-workers to yield therapeutic agents active in pernicious anæmia.

3. From the duodenal secretion of the goat and pig a substance has been prepared which is reticulocytogenic for guinea-pigs in very small amounts when injected subcutaneously.

4. The active agent is thermolabile. It is soluble in acetone and in alcohol. It is partly precipitated by mineral acids, the precipitation being more complete in the presence of salts. It is precipitated by phosphotungstic acid, lead acetate and tannic acid. It is dialysable through cellophane and collodion membranes. The molecular weight is therefore probably less than 4000. It is not destroyed by pepsin or trypsin.

We are greatly indebted to Professor Wayne, Dr. Wilkinson, Dr. Ungley and Dr. H. J. Gardner for their kindness in performing the clinical tests referred to in the text. Mr. J. H. D. Kent has had the care of the animals from which he collected the secretions. Without his assistance the work would have been impossible.