This research concerned changes involved in the formation and retrogression of medullary bone (MB), which is a tissue in the bone-marrow cavity of fowls. A total of 276 hens and 34 cocks were used. The hens ranged from 19 to 1, 744 days of age and the cocks from 2 to 857 days. The results of histological observations are summarized as follows. 1. Changes in the formation and retrogression of MB were complicated, because the phenomenon of egg-laying is complicated. 2. Particular attention was paid to patho-anatomical changes in the entire body and to anatomical changes in the ovary. An important relationship was recognized between such factors as sex, age, anatomical changes in the ovary, and patho-anatomical changes in the entire body and the formation and retrogression of MB. 3. The author compiled a complete series of histological slides showing the process of formation and retrogression. of MB in the femur. These specimens ranged from newly-foomed to completely-formed MB. This series also included a complete series of specimens showing the retrogression of MB, as well as a series of specimens showing "newly-formed secondary" MB. 4. In the course of this research, the author endeavored to make a complete survey of all the histological findings with regard to abnormal bone, transitional inclination of eosinophilic bone, formation of "eosinophilic osseous mass" (so called tentatively by the author) and other special products, in addition to the survey mentioned in the preceding paragraph 3. The histological examination of MB gave a firm and clear evidence that MB is a bone tissue which has a direct and important relation to egg-laying in fowls.

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Pathological investigation was performed on 34 chickens naturally infected with leucocytozoonosis. The results are summarized as follows. 1) The characteristic macroscopic changes observed were hemorrhages and miliary grayish-white spots in various organs and enlargement of the spleen. 2) The following host-tissue reactions occurred: Hemorrhages; inclusion of megaloschizonts by foreign-body giant cells, histiocytes, lymphocytes, and fibroblasts; swelling and proliferation of cells of the reticulo-endothelial system in the liver and spleen; lymphocytic infiltration of the liver and kidneys; necrotic foci in the liver; deposition of hemosiderin in the liver and spleen; hyalinosis of the sheathed arteries in the spleen; and focal necrosis and histiocytic accumulation in the heart and ventriculus. 3) Megaloschizonts were found in the blood vessels of various organs and adjacent tissues. They were encapsulated by reticular fibers and endothelia of the blood vessels, and filled with fine granular merozoites. Only non-capsulated megaloschizonts were present in the brain. 4) Hepatic schizonts were seen in the cyptoplasm of hepatic cells. So-calleed "early schizonts" were found in cells of the reticulo-endothelial system of the liver. Both hepatic and "early schizonts" were in the same stage and in an earlier stage than the megaloschizonts. This report is dedicated to Dr. S. YAMAGIWA, the president of Obihiro Zootechnical University (1962-), Professor Emeritus in Hokkaido University, Ex-professor in the Depart-ment of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University.

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A radiotelemeter was produced tentatively for electrocardiography (ECG). Its constitution was outlined. Experiments were conducted to make its actual adaptation possible by demonstrating its utility. The results obtained are summarized as follows. 1) The radio transmitter is a portable device, battery-operated and all transistorized. The signal is broadcast by frequency modulation on a 27.2Mc/s signal carrier with a reach of approximately 100 meters. The receiver is of super heterodyne system, relaying the ECG signal simultaneously to a conventional electrocardiograph and to an inkwriting oscillograph. 2) The electrode is a silver plate attached to a rubber cap. It is adhered to the skin with ad adhesive agent with precaution not to be dislocated by perspiration. 3) This apparatus was used to monitor human subjects in mark time, ordinary walk, stationary running action, actual fast running and hurdling, horses and riders on horseback in exercise, and horses with riders in various gaits. It gave technically satisfactory ECGs at all times, except in strenuous exertion. This apparatus was considered to be of use in functional investigation of cardiac activity, clinical diagnosis of cardiac ailment, and physiological study of locomotion.

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In the present study, observations on functional Changes in the neuromuscular system during muscular fatigue were performed on three dogs, using the electromyogram. The subjects were forced to maintain the same bipedal standing posture as described in the previous paper, for two hours. The discharge patterns of a single NMU from the gastrocnemius muscle were recorded in process of time, and the discharge intervals were measured. Each discharge-interval-time series obtained in this manner was divided into two components: a slow undulation and an irregular fluctuation. From the latter, an H-type fluctuation and an R-type fluctuation were then extracted by the conventionai method. The period of the H-type fluctuation (H) and the period (T) and decrement (Q) of the R-type fluctuation were calculated. After that, two diagrams were made. One was a correlation diagram between τ (the average of discharge-interval-time series of an NMU) and H, and the other one between T and Q. Discussion was made on these diagrams. The results obtained are as follows. 1. In accordance with muscular fatigue, the period of the H-type fluctuation increased gradually. From this fact, it may be possible to suppose that a decrease in afferent. impulse on account. of muscular fatigue causes an increase in the activity of the cortical nervous system in the control of muscular contraction. 2. The period of the R-type fluctuation was shortened immediately after standing, but it was gradually prolonged later. The preceding shortening seems to be due to an increase in afferent impulse brought about by the forced stretch of the gastrocnemius muscle. On the other hand, the succeeding prolongation is suppose to have been caused by a decrease in afferent impulse induced by muscular fatigue. 3. From these results, it may be concluded that muscular fatigue first causes a decline in the activity of the auto-regulative organization by reducing afferent impulse and then gives rise to a higher activity of the cortical nervous system in compensation for the declined activity.

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