circus movements of the heart. Such changes in impulse formation or conduction probably represent an imbalance between the various substrates and enzymes implicated in the release of energy through glycolysis, which is known to proceed over an intricate chemical pathway involving numerous stages. High concentrations of the effective sulfa drug may alter impulse initiation or propagation within the reticular gray matter of the medulla by disturbing the enzyme-substrate relationship in one or more stages, and in this way modify the development of the unstable chemicalnervous state necessary for "toppling."" I t is not clear why the drugs increase the anaerobic survival. I t is possible that depression of certain enzymes diminishes the rate 3IPdWI~l~, c. 7'. J f~l S l J~ [h, '-t, 1,0u1s. 1941, 1'. 55.7 - D a d , I'., 3 f U C l C O d ' h ~/ l , l J~l O~~J~l /111 ~f l J t / C r / l of release of anaerobic energy and thus permits continued utilization of a limited amount of available fuel. However, the apparent increase in overall energy liberation would seem to speak for an enhancing action of certain enzyme systems and an increase in utilizable fuel.Nor is it clear why sulfanilamide and sodium sulfathiazole were effective in producing the results described while equivalent amounts of sodium sulfadiazine and sodium sulfamerazine were not.Summary. Sulfanilamide and sodium sulfathiazole in non-toxic doses prolonged the survival of the anaerobic activity of the respiratory center of young rats and increased the overall energy release. Neither sodium sulfadiazine nor sodium sulfamerazine acted similarly.

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The excretion of xylose has been investigated as a further application of the method of analysis which we have already applied to the excretion of ingested creatinine (1). The method consists in analyzing separately the time change in the rate of excretion by the kidney and in the plasma concentration, after the initial disturbance produced by the rapid absorption of creatinine and its distribution in the body fluids has subsided. It was found that, in the case of creatinine, both the rate of excretion and the plasma concentration diminish exponentially in the course of time, the two functions being asymptotic to their pre-ingestion values, and furthermore, that the coefficients of the time in both exponentials are equal, on an average. Under these conditions, it was proved that the elimination of the time between pairs of simultaneous equations yields a linear relation between the rate of output and the instantaneous concentration in the plasma. It was also proved that the method provides the means of determining the errors of observation. After the constants had been calculated and the errors of observation taken into consideration, it was shown that practically all the variation in the ratio of the rate of output to the plasma concentration (called glomerular filtration rate (2) or creatinine clearance (3) ) could be accounted for.The growing literature on xylose has prompted us to study the excretion of this substance by the same method. The same interpolating functions have been found to hold as in the case of creatinine, namely, simple exponential functions of the time, asymptotic to the pre-ingestion blank levels. The only difference in the behavior of the two substances, outside the values of the constants, is that the exponential phase of decrease in plasma concentration (x) and rate of output (y) begins somewhat later after the ingestion of xylose than after creatinine. The two exponential curves will be referred to as the x curve and the y curve respectively.

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The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

A discussion of the antagonism existing between insulin and adrenalin will not be given in this preliminary report. Adrenaliii dilutions were made only at the beginning of an experiment and it is not known how much cleterioration occurred. However, the rate of injection at the beginning of the experiment was within the range of epinephrine secretion found liy Stewart and Rogoff in blood coming from the adrenal glands (0.00015-0.001 mg. per kilo per minute). More experiments are being conducted, but our results so far seem to indicate that the hypophysectomized animals require more adrenalin to prevent convulsions following insulin than animals subjected to suppression of epinephrine secretion from the adrenals. Further, it woulcl seem probable that the hypophysectomized animal does not liberate effective amounts of adrenalin during insulin hypoglycemia. C Studies of Renal Excretion of Creatinine.By studying the time change of the concentration of a substance in the plasma and of its simultaneous rate of excretion in the urine, the conclusion has been reached'' that both these quantities decrease exponentially to the pre-ingestion level and furthermore, that the coefficients of the time in both exponential functions are equal, on an average, for a given substance. From these 2 facts it follows that the rate of excretion of a substance obeying such laws is proportional to the plasma concentration at any time. The abo,ve statements have been verified so far only for creatinine and xylose.In symbols we have 2Stewart and Rogoff, Am.

Differences were observed in the ovulation rates of the right and left ovaries in response to unilateral lesions of the cervico-vaginal plexus (CVP) followed by pseudopregnancy or by anaesthesia of the CVP induced with panthocaine plus adrenaline (right ovary 6.7 +/- 0.4 (S.E.M.) vs left ovary 4.6 +/- 0.9; P less than 0.05). Pseudopregnancy (days showing a dioestrous smear after copulation with a vasectomized male before an oestrous smear following a pro-oestrous one) lasted longer in rats with a lesion in the CVP than in a control pseudopregnant group (14.9 +/- 0.5 vs 11.2 +/- 0.5; P less than 0.01). Anaesthesia of the CVP performed on each day of the oestrous cycle did not modify the ovulation rate compared with laparotomized animals. Both laparotomy and anaesthesia of the CVP performed on oestrus or day 1 of dioestrus blocked ovulation but when they were performed on day 2 of dioestrus or pro-oestrus they failed to do so (laparotomy 9/18 vs 12/14, P less than 0.05; anaesthesia of CVP 3/11 vs 17/17, P less than 0.05). The number of ova shed by the left ovary in animals with anaesthetized CVP was lower than by the right ovary (4.5 +/- 0.6 vs 6.2 +/- 0.5; P less than 0.05). These results add further support to the idea that the CVP participates in the regulation of ovulation rate, and that the left ovary is less adaptable than the right when innervation is challenged.