The anim als were p h o to g rap h ed ag ain st a sq u ared background, an d p rin ts m ade w ith th e squares enlarged to th e sam e size. E ach anim al w as th e n c u t o u t from th e p rin ts an d all m o u n ted on squ ared p a p e r a n d rep h otographed. R elativ e sizes an d body proportions can be com pared. M ethod of p h o to g rap h y a n d rep ro d u ctio n as in P la te 14. 612.313The secretion of protein m aterial in the parasym pathetic subm axillary saliva This paper deals with a study of the secretion of protein material by the submaxillary gland of the cat in response to electrical stimulation of the chorda tympani nerve. In the attempt to make a more generous use of certain advantages offered by physical methods in research on the digestive glands, the submaxillary gland was chosen for the initial investigation because of the relative ease of physiological experimentation. The study is characterized by (1) the use of quantitative spectroscopic methods of analysis which permit an extension in the range of the investigation over that possible with a purely chemical procedure, and (2) the application of mathematical analysis in the interpretation of the results.

The concentrations of sodium, potassium, calcium, chloride, bicarbonate, and protein and non-protein nitrogen were determined in series of samples of pancreatic juice secreted by dogs in response to (a) constant rate of administration of secretin, (b) varied rate of administration of secretin, and (c) interrupted administration of secretin (rest period, 2 hr.). Spectroscopic as well as chemical methods were used in the analysis of the samples.The data indicate that the membranes of the pancreatic gland offer little resistance to the passage of simple inorganic ions. The compensatory relation between the bicarbonate and chloride concentrations of the secretion is interpreted on the basis of (a) formation of at least part of the bicarbonate within the secretory cells, and (b) the action of membrane forces, probably of an electrical nature. Absorption spectrum studies indicate either (a) that only one type of absorbing protein is present in the secretion, or (b) that if several types are present, they are always secreted in constant proportions whether they are enzymatically active or not. The interpretation of the protein nitrogen and certain other data are given in a subsequent paper.

Summary.The cytoloxlc efTects of hyperthermia on tumours are readily measured. l';iramelers of injury to normal tissues are needed to evaluate therapeulic potential.Fifty-five isolated rat livers were perfused in vitro for 180 min in order to determine parameters of hyperthermic injury. During this period they were heated for I h at lemperaiures ranging from 37° to 45° and then assessed for evidence of hyperthermic injury.The most critical indicator of hyperthcrmic injury was sustained depression of bile production. Bile sccreiion decreased by 80% after heating at temperatures above 42°. A^partate amino transferase (AST) release increased significantly at temperatures of 42° and above.Potassium and variable amounts of glucose were released into the medium during heating, reflecting temporary changes in melabolism at high temperatures.

A mathematical treatment of the process of synthesis of protein material in the pancreas, and its secretion in response to secretin administration, has been developed. It was based on assumptions inferred from experimental data and from analogy with a suggested mechanism for the submaxillary gland, published previously. It leads to expressions that quantitatively describe the protein output in samples of pancreatic juice obtained under widely varied experimental conditions. Inferences concerning the fundamental character of certain glandular mechanisms may be drawn from the treatment. In addition it permits provisional calculation of various factors not directly observable in critical experiments, and suggests further problems in connection with the secretory processes.

A study of the transport of material in the condensed d-c. spark discharge has been made, with the object of placing quantitative spectroscopic methods of analysis on a less empirical basis and thus permitting, (a) the recognition of certain conditions of source operation which lead to unreliable determinations, and (b) the determination of some of the criteria to be fulfilled for maximum precision in analytic measurements.Variations in the transport phenomena, as indicated by variations in the relative distributions of emitting atoms of various elements along the discharge axis on the addition of certain substances to a sample, appear to be closely connected with the ionization potentials and masses of the elements, and with the ionization potentials of other particles present in the discharge. The data indicate the necessity for the use of a spectroscopic buffer, and provide certain criteria for the choice of the buffer and of the internal standard element.The exact nature of the mechanism of transport is uncertain, but various considerations indicate that neither the motion of ions under the influence of the field nor diffusion in the ordinary sense is sufficient to account for observed features.