J. Lorrain Smith

The Oxygen Tension of Arterial Blood

THE chief interest of the present investigation centres round the question whether diffuision alone explains the transference of oxygen fromn the air of the pulmonary alveoli into the blood, or whether other important factors are concerned in this process. If the oxygen tension of the blood leavina the alveolar capillaries is always, or even occasionally, higher than that of the alveolar air, diffusion alone evidently cannot explain the transference. The analogy presented by other organs of absorption or excretion would perhaps lead us to believe that absorption of oxygen by the lungs is probably not due to any simple physical process such as diffusion. On the other hand it does not seem at all clear that any physiological advantage would accrue fronm an active absorption of oxygen by the lungs. The red corpuscles of blood, saturated with air of alveolar oxygen tension (about 140/ of an atmosphere in man), would contain very nearly as much oxygen as the haemoglobin is capable of absorbingo, so that any further increase in the oxygen tension of arterial blood would imply only a very trifling increase in the quantity of oxygen taken up by the blood. If, therefore, the exposure of the blood to the alveolar air is sufficiently prolonged under all ordinary circumstances for saturation to occur by diffusion alone, no appreciable advantage would apparently result from an active absorption of oxygen. On this point however we have no experimental data, so that there is thus not much

On some Effects of Thyroidectomy in Animals

ABOUT the year 1883 Kocher and Reverdin published their wellknown observations on the effects of thyroidectomy in the human subject. Attempts had previously been made by physiologists to discover the function of the thyroid gland by means of experiments on animals, but these had been practically unsuccessful for a reason which has become clear in the course of subsequent research. After it had been shown by Horsley that myxoedema, or a condition essentially similar to it, follows the ablation of the gland in certain species of animals, it became evident that we must recognise two different modes in which the effects of the operation may show themselves. In the first place, in certain animals, such as cats and dogs, we bave as a rule a rapid development of the most pronounced symptoms indicating extreme irritation of the nervous and muscular systems, and this condition is followed by a fatal termination in the great majority of instances. On the other hand, in man, in monkeys as well as in exceptional cases in the other groups already mentioned, we may have the slowly developing changes which correspond to myxoedema. It is unnecessary here to enter into the controversy in regard to the effects of the operation on animals such as rabbits. It was till recently believed that in the case of rabbits the removal of the thyroid gland had little or no appreciable effect. Gley1, however, has pointed out that the reason for this is to be found in the existence of accessory thyroids, which are able to take on the function of the ablated gland.

The Pathology of the Red Degeneration of Uterine Myomata.

CASE 1. Z.G., age 28, was admitted to St. Mary’s Hospital on November 12th 1907, complaining of an abdominal swelling and much constitutional disturbance. She stated that she had first noticed the lunip after her second confinement, but that it gave rise to no inconvenience at that time, or even during her third pregnancy. This pregnancy cndcd in a full-tcrm natural labour, three months previous to admission. Two days aftcr her confinemrnt she felt very ill, with great weakness and nausea, and since then had been pmctirally confincd to brd. On admission she looked thin and pale; her temperature was normal, but the pulse rate was almost constantly 120. A smooth round mass could be felt in the lower part of the abdomen, almost central, and rising an inch and a half above the umbilicus. On vaginal examination the cervix appeared t o he pulled iip and attached to the mass felt in the abdomen. On opening the abdomen, Noremhcr 16th 1907, the tumour was found to be closely adherent t o the abdominal wall, and to the surrounding intestines. The adhesions were vciy firm, and some time and care were required in scparating them. The tumour was then found to be a uterine fibroid, and supra-vaginal hysterectomy was