I. EFFECTS OF THE INTRAVENOUS INJECTION OF COLLOIDAL SILVER UPON THE HEMATOPOIETIC SYSTEM IN DOGS.

1. Colloidal silver has no specific action on the bone marrow in dogs but is a systemic poison which may cause anorexia, weakness, loss of weight, anemia, and death. 2. Hemolysis can be demonstrated after large doses of colloidal silver and the anemia presumably is due in part at least to a destruction of red blood cells in the peripheral circulation. 3. The colloidal silver, injected intravenously, is deposited as granules almost exclusively in the cells of the reticulo-endothelial system after the manner of particulate substances. 4. Repeated injections of non-lethal amounts of this substance are invariably followed by hyperplasia of the bone marrow. In no case was aplasia found. 5. Large single doses of this material cause rapid death in 12 hours or less characterized by pulmonary edema and congestion. 6. An initial increase in the number of erythrocytes and leucocytes may occur following smaller amounts of silver, but repeated injections cause a considerable anemia, without a definite increase in the leucocytes and with no signs of blood platelet deficiency.