1. In the course of this investigation we have dealt with many cases of refection, but during a period of several years we never obtained the condition except when raw potato starch was the carbohydrate in the synthetic diet. Recently, in the exceptional circumstances described in the text, we have had a few cases with rice starch. 2. Like other authors, we have always found that in refected rats the caeca are always enlarged and their contents the seat of specially great bacterial activity. The nature of the dominant organisms present has varied from case to case, and in one it was apparently a yeast. Nevertheless, there is a suggestion that certain organisms are more potent in promoting refection than others. In rice starch refection, such organisms seem to be present. 3. We have found that the administration of roughage in the manner described can, to a large extent, prevent the establishment of refection. The number of organisms in the caeca is then greatly reduced and the contents indeed may become nearly sterile. 4. Using potato starch as the carbohydrate of the diet, we have had no difficulty in reproducing the results of the early experiments published by one of us (Hopkins, 1912), but we found that to obtain a growth induced by administering very small quantities of milk to vitamin-free diets, the presence of this starch is necessary. Indeed, the growth so promoted calls for the same particularity in the carbohydrate supply as does the establishment of refection. 5. Nevertheless, we have obtained what seems to be conclusive evidence showing that the growth with milk is wholly independent of refection. 6. We have obtained some evidence that potato starch contains growth factors in association with protein which only becomes soluble when liberated by treatment with pepsin HCl. As our experimental results bearing on this, for some reason at present unexplained, have lacked constancy, we can only claim, that they are suggestive.
The experiments described in this paper have shown that the purine base hypoxanthine, added in suitable concentration to a medium commonly used for tissue culture, is capable of markedly increasing both the rate and duration of the tissue growth. On the other hand, the related base adenine acts unfavourably on the growth. The nature of the influence of the former base is perhaps not clear, but certain possibilities are discussed.
of biochemistry in the University of Cambridge has recently been announced, has for some time been recognized as one of the most distinguished biochemists
MR. G. D. PRESTON, whose appointment to the Harris chair of physics at University College, Dundee, has recently been announced, is best known for his applications of physical methods to metallurgical problems. After leaving Cambridge, he joined the staff of the National Physical Laboratory, working first in the Physics Department and later in the Department of Metallurgy. His chief interest has lain in X-ray crystallography and more particularly in its applications to metallurgy. In collaboration with Prof. B. A. Owen, he was one of the pioneers in the investigation by X-ray methods of alloy systems, and succeeded in determining the structure of various alloys and alloy systems. In addition to his work in the X-ray field, he has also applied the method of electron diffraction successfully to problems of metallurgy and to the study of corrosion. He was one of the first in Great Britain to construct and use the electron microscope. Mr. Preston's more recent work has been concerned with the age-hardening of alloys. During these investigations he found the diffuse X-ray reflexions which have been the subject of so much experiment and discussion of late. His work has thrown much light on their nature and origin. His researches have been notable for the fact that they have been carried out almost entirely with apparatus designed and constructed in his own laboratory, and much ingenuity has been shown in producing equipment essentially simple, but eminently suited for the task in hand. It is to be hoped that in his new sphere Mr. Preston will have ample opportunities for further research.
THE report on the operation of the Colonial Development and Welfare Act, 1940, to October 31, 1942, and, more especially, Sir Frank Stockdale's report on Development and Welfare in the West Indies, 1940-1942, give a very clear picture of the ideas which are inspiring Great Britain in the discharge of its responsibilities to its Colonial dependencies at the present time. There can be no question that the future of the world depends largely on the ability of Britain and the United States to understand one another and to work together, and questions of Colonial policy must inevitably involve a searching test of that capacity for co-operation. It would be most unfortunate if Colonel Oliver Stanley's speech at Oxford on March 5, with its firm rejection of international administration of the Colonies, were misinterpreted as implying the denial of the rights of third parties to take an interest in the Colonial policy of the Colonial Powers.
of biochemistry in the University of Cambridge has recently been announced, has for some time been recognized as one of the most distinguished biochemists
The experiments in this paper have been chiefly concerned with a derivative from pterins, the wing pigments of pierid butterflies. These pigments have become prominent of recent years, partly on account of the prolonged efforts (1925-41) of continental workers to determine their nature. The progress of these constitutional studies has quite recently become dramatic, as is made clear in the historical introduction below. Moreover, one pterin at least has been shown to occur in mammalian tissues, with probable physiological functions there. From one pterin (erythropterin) the yield of the derivative with which the present study has dealt is large. From another (xanthopterin) it arises only in special circumstances which are of considerable interest. The substance gains in interest from its mode of origin. This involves an oxidation by molecular oxygen in solutions of low pH. On the acid side of neutrality its formation proceeds throughout a wide range of pH values, but not at all on the alkaline side. The properties and behaviour of this derivative (which in some respects are exceptional) are described, and among the experimental results obtained are some which offer guidance for future extension. The ground covered has been limited, however, by difficulties at the present time in obtaining an adequate supply of material. No evidence bearing on the actual constitution of the product has yet been obtained, and the paper represents what is essentially a preliminary study. It seems justifiable to claim, however, that until the structure of this derivative is determined and the mechanism of its formation made clear, the chemistry of the pterins will remain incomplete. Another section of this paper deals briefly with the yellow products which occur when aqueous suspensions of uric acid are heated in sealed tubes at high temperature. These show properties strikingly akin to those of the pterins, and in particular yield purple derivatives in precisely those circumstances which lead to the formation from the natural pigments of the product here dealt with which they closely resemble.
Czechoslovakia, described Comenius's plans for peace leagues and his place in history
IT has long been held that the succinic dehydrogenase requires no co-enzyme or intermediary hydrogen carrier to link its activity with that of the cytochrome system.
UNTIL the end of the first decade of the present century, official teaching concerning the nutritional needs of the human body was still based on the results of classical studies by Carl Voit and Max Rubner and on the views of the Munich School thence derived. The adequacy of a dietary was measured in terms of calories and protein alone. It was generally believed, alike by the academic physiologist and by those concerned with practical dietaries, that, questions of palata-bility and digestibility apart, so long as the food of an individual provided sufficient potential energy for the activities of his internal organs and for the external mechanical work he might be called upon to do, the only demand of a more specific kind made by his body was for a certain, rather ill-defined, minimum of protein, to subserve the growth and maintenance of its tissues. Beside the carbohydrates, fats and proteins which provide these essentials, natural foods were known, of course, to contain a variety of other substances. These, however, are present individually in very small amount, and except for certain minerals among them, necessary for the formation of bone and for the maintenance of particular physical conditions in the body, they assumed to be without nutritional importance.
I THE British Association returns to Leicester with assurance of a welcome as warm as that received twenty-six years ago, and of hospitality as generous. The renewed invitation and the ready acceptance speak of mutual appreciation born of the earlier experience. Hosts and guests have to-day reasons for mutual congratulations. The Association on its second visit finds Leicester altered in important ways. It comes now to a city duly chartered and the seat of a bishopric. It finds there a centre of learning, many fine buildings which did not exist on the occasion of the first visit, and many other evidences of civic enterprise. The citizens of Leicester on the other hand will know that since they last entertained it the Association has celebrated its centenary, has four times visited distant parts of the Empire, and has maintained unabated through the years its. useful and important activities.
AMONG the many aspects of progress in physics which tempt reference is that concerned with cosmic rays, so fascinating to most minds are speculations concerning their nature. Thinking of the more recent developments in this subject, one would like to express admiration of the enterprise which has enabled Prof. E. Regener to obtain records from many miles up in the atmosphere and deep below the surface of Lake Constance for measurements of their varying intensity; admiration no less for the similar enterprises of Compton and Kolhorster. It is interesting to learn that Regener, as the result of the most recent researches by himself and colleagues, has formed the personal opinion that a part at least of cosmic radiation is electromagnetic.
Journal of the Society of Chemical IndustryVolume 52, Issue 36 p. 719-729 Article Some chemical aspects of life† Sir Frederick Cowland Hopkins Pres. R.S., Sir Frederick Cowland Hopkins Pres. R.S.Search for more papers by this author Sir Frederick Cowland Hopkins Pres. R.S., Sir Frederick Cowland Hopkins Pres. R.S.Search for more papers by this author First published: 8 September 1933 https://doi.org/10.1002/jctb.5000523602 † Presidential address to the British Association for teh advancement of science, at Leicester, on Sept. 6, 1933. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Volume52, Issue368 September 1933Pages 719-729 RelatedInformation
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