Harvey Cushing

Alterations of intracranial tension by salt solutions in the alimentary canal

In two interesting and suggestive papers 1 Weed and McKibben demonstrated the significant physiological fact that it is possible to reduce the cerebrospinal fluid pressure and diminish the bulk of the brain by injecting a hypertonic solution into the blood stream. Conversely they found that hypotonic solutions had the opposite effect: a rise of cerebrospinal fluid pressure and an increase of brain bulk. In the course of our studies their work has been repeated and their general conclusions confirmed. The clinical bearing of these facts is obvious. Particularly they concern the states commonly referred to as “pressure symptoms.” By similar methods it has been found possible to secure these same results in patients with increased degrees of intracranial tension. It was felt that the undesirable effects on pulse, respiration and blood pressure of such intravenous injections might contraindicate their use. For this reason the effects of gastrointestinal doses of hypertonic solutions were studied. In a large series of animal experiments it has been found that practically the same effects may be obtained by the gastrointestinal route of administration. By this method the intracranial changes are not attended by disturbances of pulse, respiration or blood pressure, also the possible alterations of the cellular elements of the blood are avoided. Twenty to thirty cubic centimeters of a saturated sodium chloride solution introduced into the duodenum or rectum of an average-sized cat produced a maximal fall of cerebrospinal fluid pressure precisely comparable to that which occurred when the solution was given intravenously. Following such doses the average fall of pressure in a large series of experiments was 258 mm. normal saline. The changes were roughly proportionate to the concentration of the salt and the size of the dose.

SUBTEMPORAL DECOMPRESSION IN A CASE OF CHRONIC NEPHRITIS WITH UREMIA; WITH ESPECIAL CONSIDERATION OF THE NEURORETINAL LESION

S FROM CURRENT MEDICAL

Hibernation and the pituitary body

A train of symptoms, coupled with retardation of tissue metabolism and with inactivity of the reproductive glands, not only accompanies experimental states of hypophysial deficiency but is equally characteristic of clinical states of hypopituitarism. The more notable of these symptoms are a lowering of body temperature, slowing of pulse and respiration, fall in blood pressure, and somnolence, together with a tendency, in the chronic cases, toward an unusual deposition of fat. These symptoms are comparable to those accompanying the state of hibernation. In a series of hibernating animals (woodchucks) it has been found that during the dormant period the pituitary gland not only diminishes in size but undergoes extreme histological alterations, chiefly evident in the cells of the pars anterior, which completely lose their characteristic differential reactions to acid and basic stains. At the end of the dormant period the gland enlarges and the cells regain their characteristic staining reactions. On the basis of this observation hibernation may be ascribed to a period of physiological inactivity, possibly of the entire ductless gland series, but certainly more especially of the pituitary body, not only for the reason that the changes in this structure are particularly apparent but because deprivation of the secretion of this gland alone of the entire series produces a train of symptoms comparable to those of hibernation.

The pars anterior and its relation to the reproductive glands

We wish to report briefly some of the results obtained thus far by the feeding of dried extract of bovine hypophysis to young rats of pure breed and known pedigree. The animals were taken as soon as weaned at the age of three or four weeks. In each instance the experiments were controlled by observations on other rats of the same litter, kept under similar conditions without grandular administration. A known weight of dried extract (.1-.05 gm.) was given daily in a bread and milk pill, and over varying lengths of time, after which the animals were sacrificed and the reproductive glands examined. Both anterior and posterior lobe extracts were used and in several instances ovarian or corpus luteum extract was given in equal dosage to the control animals, to rule out the effect of administration of glandular extracts in general. In a limited number of instances pairs of young rats of the same litter were taken, one pair being given small quantities of extract of pars anterior, the other pair used as a control. The animals fed with the extract bred sooner and oftener than the controls. Posterior lobe extract of pituitary gland had no such effect. Conclusions.—The following conclusions seem warranted: I. Pituitary extract, and particularly extract of pars anterior, has a markedly stimulating effect upon the growth and development of the reproductive glands in young rats of both sexes, as evidenced by histological examination. II. Extract of pars anterior tends to cause early and frequent breeding. Posterior lobe extract has no such effect. III. Posterior lobe and ovarian (corpus luteum) extracts apparently do not stimulate sexual development.

THE LIFE OF SIR WILLIAM OSLER

An electrophoretic imaging process wherein a suspension of particles in a carrier liquid are placed between a photoconductive electrode and a second electrode. With an electrical field applied between the photoconductive electrode and the second electrode the photoconductor is exposed to imagewise radiation which causes particles on the surface of the photoconductive electrode to be driven away in image configuration by charge exchange with the photoconductive electrode. The migrating particles form a negative image on the second electrode leaving a positive image behind on the photoconductive electrode.

Medical ClassicMedical Classic The functions of the pituitary body1

(Editor’s Note: This Medical Classic is reprinted in its entirety, followed by an invited commentary by Nicholas P. Christy, M.D. It appeared in AJMS 139; 473-84, 1910.

Medical Classic The functions of the pituitary body11Read at the combined session of the American Physiological Society and Section K of the American Association for the Advancement of Science, Boston. December 29. 1909.

(Editor’s Note: This Medical Classic is reprinted in its entirety, followed by an invited commentary by Nicholas P. Christy, M.D. It appeared in AJMS 139; 473-84, 1910.