The purpose of the present study was firstly, to investigate the actions of Ca++ and Na+ ions on the release and synthesis of ACh, respectively, in homogenates of cholinergic neurones, in order to gain further information concerning the role of these ions in ACh metabolism. The second purpose of this study was to test the hypothesis proposed by Birks that changes in intracellular sodium ion levels may provide a general mechanism for controlling a wide variety of metabolic processes in active cells. [...]

For many years, measurements of the light transmittedby thin films of nonhemolyzed whole blood have been usedfor estimating oxygen saturation. More recently, rafleetancemeasurements of thick layers of nonhemolyzed bloodhave been used for the same purpose. The lack of precisionof these empirical techniques suggested to us t'hat morebasic work was required to investigate the light scatteringand absorbing properties of nonhemolyzed blood. [...]

From the 1790 's, when Galvani and Volta (R. M. Green, 1953) experimented with animal electricity, until the beginning of the 20th century, there was little reason to doubt that excitation passed from nerve to muscle electrically (Kuhne, 1888). Protoplasmic continuity was assumed, despite increasing evidence to the contrary, until about the turn of the century. [...]

Traditional concepts (Bayliss, 1923) concerning the functional organization of the nervous structures controlling the cardio-vascular system, assign to the medulla oblongata a predominant role both in the maintenance of a background neurogenic tone and in the mediation of adaptive and homeostatic responses to changes in sensory input. In this scheme the role of the spinal cord is secondary; the cord's capabilities for maintenance of background tone and for adaptive and homeostatic responses, when its connections with the higher centres are severed, are considered negligible. Instead, the neurones of the vasomotor centre in the brain stem are believed to be the site where convergence and integration of inputs takes place, the true final common path of the system. [...]

The constancy of the red cell mass in the normal body constitutes a fine example of homeostasis and for this reason many investigators including the writer have been led to study, from varying aspects, the physiological mechanisms underlying the process of erythropoiesis. [...]

The discovery by Loewi (1921) that the slowing of the heart during vagal stimulation was due to the release at the nerve ending of a chemical substance, led to the study of transmission at other synapses. Although much success has been achieved at various periferal synapses, no chemical transmitter at the G.N.S. synapses has definitely been discovered or proven. The complexity of the G.N.S. is such that many supposedly similar experiments give conflicting results. One explanation for these conflicting results obtained when dealing with the G.N.S. would be that there is probably more than one synaptic transmitter, and that a substance may be excitatory at one synapse but inhibitory at another.

Following a method designed by Burgen and Stewart for measuring the fluid turnover in the pleural cavity (J. Lab. & Clin. Med. 52: 118(1958).), analogous studies were carried out on the dog made ascetic by constriction of the inferior vena cava above the diaphragm. Radioiodinated albumin was injected intraperitoneally and the lymphatic absorption of fluid was calculated from the appearance of the label in the circulation, the non-lymphatic flow (usually formation) from its dilution in the effusion. The resting turnover of the unanaesthetized dog was studied. The non-lymphatic flow was found to be consistently larger than the lymphatic absorption in all the experiments but one in which the dog was "maximally ascitic", that is, where the abdomen appeared by inspection to be maximally filled with fluid.

The effect of tonicity on the rate and amount of histamine released from several in vitro preparations was studied. In hypertonic (1.2M) solutions of sucrose or mannitol, basic histamine liberators released significantly less histamine from dog liver particles, isolated mast cells, perfused guinea pig lungs, and perfused cat paws, than they did in isotonic solutions. When surface-active compounds were used as histamine liberators, no significant differences were found in the amount of histamine released in the two kinds of solution. [...]

Pharmacological evidence suggests that the sympathetic supply to the blood vessels of the cat's submaxillary gland is adrenergic; but the most conspicuous response of these vessels to sympathetic stimulation is dilatation. Since the existence of adrenercic vasodilator fibres is controversial, the mechanism of this sympathetic vasodilatation has been investigated. It has been found that the sympathin released within the gland is mainly noradrenaline but contains a substantial proportion of adrenaline. [...]

“Histochemistry deals with the chemistry of tissues." Or, "histochemistry deals with the chemical characterization of substances in their natural locations within cells and tissues." These definitions furnish the introductory statement to two excellent reviews on the subject by Gersh (1941) and Dempsey and Wislocki (1946). Histochemistry is a relatively young science. As evidence for this, one may cite the very recent publication of the first textbook of Histochemistry (Pearse, A.G.E.: Histochemistry, Little, Brown and Co., Boston, 1953), and the establishment of the first journal devoted to publications within this field (Journal of Histochemistry and Cytochemistry, The Histochemical Society, 1953).