[Effect of illumination of the chick embryo on hatchability, length of incubation and hematopoiesis].

In the incubator, illumination had no effect on the hatchability but it reduced the length of incubation. In the hatchery, it had no effect. Erythropoiesis and lymphopoiesis were stimulated by continuous illumination but the enhancement of the total number of erythrocytes was due to the enhancement of embryonic ones. Thermic stress during the incubation period induced an early appearance of blood leucocytes.