THE investigations recorded in the present paper have arisen out of the study of the local reactions of the cutaneous vessels by one of us (1) Finally we shall attempt to synthesise our results into a picture of the innervation.Methods. We have generally narcotised the frogs for the operations with urethane giving curari later when necessary. Operations, from which the animal is left to recover, require a number of precautions which were only gradually and, we fear, incompletely made out. Rana esculenta appears to stand the operations better than R. temp., but for

What is reported in the following pages is an example of work achieved in a relatively short time by the co-operation of a sufficient number of institutions and individuals. The venue of this research was in the Andes, and the work was carried out in the winter 1921-1922, yet its organisation only commenced definitely in the early summer of 1921, when a group of British and American physiologists secured the support of the various universities or other institutions to which they were attached. This support was given in the most ungrudging way. It included the liberation from immediate duty of the members of the party, often at considerable inconvenience to those who remained at home, the loan of apparatus, the contribution of substantial funds, and a great body of goodwill, which was perpetually translating itself into increased efficiency of the work actually accomplished. The following collaborated in one or more of the ways indicated above:— The Department of Physical Chemistry of Harvard University. The Proctor Fund of Harvard University. The Elizabeth Thompson Fund. The Rockefeller Institute of Medical Research, New York City. Columbia University.—From a fund, to which contributions were made by Dr. Walter B. James, Mr. Cleveland H. Dodge, and a contributor who wishes to withhold his name, but to whom thanks are none the less due. The Royal Society of London. The Research Grant to the Physiological Department of the University of Toronto. The Moray Fund, Edinburgh. The Carnegie Fund, Edinburgh. Sir Robert Hadfield, Bart., F. R. S. Sir Peter Mackie, Bart.

The oxygen and carbon dioxide content of the blood in man, both in normal and in pathological conditions, has been studied but little, although the close relation of variations in the blood gases to alterations in the respiratory and circulatory mechanisms and to the blood flow has long been recognized. The difficulties of gas analysis upon small quantities of blood and in the technique of collection of samples have rendered the data hard to obtain and the reports in the literature scanty.

In the preceding papers (1, 2), we have described the phenomena produced by the cessation of injections of suprarenal cortical extract in the suprarenalectomized adult dog, which has been maintained in a normal state of nutrition, with well healed incisions, for a period of several weeks after suprarenalectomy. We have pointed out that death in such an animal, if injections of the hormone are not resumed, is due to a condition of shock produced by loss of body fluid. The observed sequence of events is: hemoconcentration, which becomes more and more marked; progressive loss of body weight; anorexia; lowered body temperature and basal oxygen consumption; muscular weakness; vomiting and diarrhea; and ultimate failure of the circulation, as indicated by diminished blood flow and fall in blood pressure. These symptoms are associated with a progressive rise in blood nonprotein nitrogen (urea) concentration, a drop in plasma chlorides, and, as we have recently shown (1), a fall in plasma total base. The present communication is concerned with an analysis of the factors producing this hemoconcentration and of the train of phenomena which then follows it. 1 1 We wish to acknowledge the assistance of Dr. Mary Buell in organizing the chemical procedures involved in the manufacture of the cortical extract and in the selection and setting up of analytical methods used in the studies herein reported.We are indebted to Miss Margaret Strauss who has made lactic acid, inorganic phosphorus, and calcium estimations on a series of animals before and during insufficiency.