In many clinical conditions involving the hematopoietic organs, cholesterol and lecithin show deviation from the normal, indicating that in some way, directly or indirectly, the metabolism of these substances may be intimately related to the functioning of the blood-forming tissues.1 A very small amount of data is available, however, which definitely correlate a functional physiologic state of the hematopoietic organs with the lipoids of the blood.
It is well known that exposure to low barometric pressure, that is, to low oxygen tension, will cause a stimulation of the blood-forming organs. This has been repeatedly verified2 since Viault3 demonstrated that the peripheral blood of man in passing from a low to a high altitude shows an increase of red blood cells and hemoglobin. Zuntz and his associates4 and Dallwig, Kolls and Loevenhart5 also found evidences of stimulation of the bone marrow in animals subjected to low oxygen tension. From their experiments