The initial changes of the adrenal apoplexy in young adult Sprague-Dawley's rats, injected by a big dosis of 7,12-dimethylbenz(α) anthracene(emulsion)intravenously, were compared morphologically with the patchy hemorrhages in the adrenal cortex of adult rats of the same strain, injected by a sublethal dosis of Polybrene (solution) intravenously. The morphological observations were performed mainly by means of some histochemical methods for enzymes and electron-microscopy. A hemorrhagic necrosis in the adrenal cortex was detected in the almost all rats injected with either 5 mg of 7,12-DMBA or 7.5 mg of Polybrene at a certain course after the injection. For the control, it is observed neither Fatgen-D (fat emulsion for nutriment) nor saline solution induced a necrosis with hemorrhage in the adrenal cortex of the experimental animals. The adrenal bleedings occured macroscopically 1/2-4 hour after the injection of Polybrene. Some wedge-shaped infarcts (necrosis with hemorrhage) were recognized histochemically earlier than by the routine methods. The electronmicroscopic findings revealed that some blood cells agglutinated in the sinusoids, the endothels of which were not injured in the early stage, and that both severe swellings and prominent destructions of the internal structures were developed at the whole mitochondrion only in the damaged adrenocortical cells distributed focally in the fasciculate of the adrenal cortex. It was concluded that Polybrene did produce thrombi at first in the long and exceedingly narrow sinusoids in the middle layers of the adrenal gland by its electrochemical basis, that ischemic alterations in some adrenocortical cells were induced secondly with the circulatory disturbance, and that finally patchy necroses with hemorrhages were exhibited focally in the inner adrenal cortex. The adrenal apoplexy was demonstrated on the naked eyes more than 36 hours after the injection of 7,12-DMBA. However, pycnotic nuclei and decreases of the histochemical activity of acid phosphatase were detected in the mottled area of the inner adrenal cortex within 24 hours. The histochemical activities of the dehydrogenases in the adrenal cortex became less intense diffusely or mottled 24-30 hours after the administration and were hardly detected on the 2nd day. They disappeared completely in the necrotic areas on the 3rd day. Not only pseudoplasmal reaction but also Baker's test for phospholipids changed in the same manner as the histochemical reactions of dehydrogenases in the course of the adrenal injury by 7,12-DMBA.
I) Ten days after a unilateral adrenalectomy had been performed on rabbits, the other adrenal gland was also removed and the consequent changes in the blood picture were observed. 1) The co m pletely adrenalectomized rabbits showed a gradual decrease in R. B. C. count, which reached its minimum in from one to two weeks. Recovery to th e normal level could not be obtained within one month. 2) The color index began to rise gradually a b out one week after adrenalectomy. 3) The reticulocytes increased after one week, and then returned t o normal. 4) As to the diameter of the erythrocytes, a shift to the right in the Price-Jones' curve was observed from about eight days after the adrenalectomy. 5) As for W. B. C. count, no remarkable change was obse r ved. 6) Neutropenia with relative lymphocytosis was reco g nized in the differential W. B. C. picture. 7) The eosinophils showed a slight increasing tendency. 8) In the bone marrow pictures, a decrease of erythroid cells, especially in immature erythroblasts was observed. As for the myeloid system, an increase in immature pseudoeosinophils and a decrease in mature ones were found. Histological examination of the bone marrow further revealed a remarkable hypopla sia of the erythroid system. 9) The rate of pseudoeosinophils with toxic granules showed marked increase about three weeks after the adrenalectomy; i. e.39.3% in the peripheral blo od and 22% in the bone marrow on the average. The toxic granules appeared in the myelocytes at the highest rate, and, in the other cells, they appeared in the following order: metamyelocytes, staff cells, and segmented cells. II) Intravenous injection with anti-rabbit-adrenal guinea pig serum caused anemia, decrease in the pseudoeosinophil/lymphocyte ratio in the peripheral blood, and hypoplasia of the erythroid cells in the bone marrow. These changes are similar to those found in the adrenalecomized animals. Histologically, a remarkable degeneration of the adrenal cortex (zona glomerulosa and zona fasciculata) was observed in the rabbits treated with the antiserum.