Page Diseases due to Penrersion of Nutrition 455 Waste Products of Proteid Metabolism may be Dangerous to Health 456 Origin and Significance of Uric Acid 458 Modification of Uric Acid Excretion by diminishing the amount of Proteid Food 463 Tables showing Excretion of Uric Acid by the three groups of men under observation ; Uric Acid per kilo of Body- Weight, etc. — For the benefit of lay readers, metabolism, a word frequently made nae of, may be defined as a term applied to the collective chemical changes taking place in liying matter. Voit, however, with many other physiol- ♦ Ein Stoffwechselversuch an Vegetarianern. 144 " ration, and there is almost univei-sal belief in the efficacy of a rich and abundant diet to strengthen the body and to increase bodily and mentiil vigor. None, apparently, other than that which comes from the customs of genemtions of high living.
The chief criticism of Kirschfeld's experiments ia that he failed to obtain in all ciiaes definite analytical data of the food-stuffs employed and failed to determine the nitrogen of the faeces. What is the minimal proteid requirement for the healthy man, or rather, how far can we safely and advantageously diminish otir proteid intake below the commonly accepted standards? Thus, Munk * some years ago (1893) sounded a warning on this point which was later confirmed by Rosenheim.! If this is true, it is obvious that the living substance of the tissue protoplasm must be slowly formed from the proteid of the diet. Popular Science Moathl^i Jtme, IQOa PHYSIOLOGICAL ECONOMY IN NUTRITION 15 equilibrium on a low proteid diet and great physiological economy as shown by the low fuel value of the food consumed, coupled with remarkable physical strength and endurance.
In 1888 Hirschfeld,f again experimenting on himself, maintamed nitro- gen equiiibriuni for seveml days on 7,5 grams of niti^gen per day, with fats and carbohydrate sufficient to yield a total fuel value of 3462 hirge calories as the daily average. This question brings us back to the starting-point. Further, Jaffa, in harmony with Siven, believes that after the body has suffered a loss of nitrogen, there is at once an effort to attain nitrogenous equilibrium, and that any gain of nitrogenous body material is a comparatively slow process. t Further Investigations among Fruitarians at the California Agricultural Experiment Station. Fletcher per- forms this work with giiose here to discuss how far these results are due to insalivation, or the more thorough mastication of food- The main point for us is that we have here a striking illusti-ation of the establishment of nitrogen • For A fu Uer acconiit of thii itud^, «ee Chitlenii^n, Phytiologicftl Economy in Natrilioa.
Maintain attribution The Google "watermark" you see on each file is essential for informing people about this project and helping them find additional materials through Google Book Search. Keep it legal Whatever your use, remember that you are responsible for ensuring that what you are doing is legal. ACKNOWLEDGMENTS OP FINANCIAL AID IN MEETING THE EXPENSE OF THE EXPERIMENTS HEREIN DESCRIBED The writer has been most generously aided by substantial grants from the Bache Fund of the National Academy of Sciences, and from the Carnegie Institution of Washington ; also by large donations from Mr. Efficient aid in the routine chemical and other work of the laboratory in connection with the experiments has been ren- dered by Frank P. Fuiiher, the elimination of excessival amounts of these crystalline nitrogenous bodies through die kidneys places upon these organs an unnecessary burden which PHYSIOLOGICAL ECONOMY IN NUTRITION 17 is liable to endanger their integrity and possibly result in seri- ous injury, to say nothing of an early impairment of function.
Do not assume that just because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other countries. The present experiments were undertaken to throw light upon this broad question of a possible physiological economy in nutrition, and with special reference to the minimal proteid requirement of the healthy man under ordinary conditions of life.
Whether a book is still in copyright varies from country to country, and we can't offer guidance on whether any specific use of any specific book is allowed. «t Published in No Tcmlier, 19(M TIIK VMVEKSITV HKE! The writer as a student of physiology has always main- tained that man is disposed to eat far more than the needs of the body require, but his active interest in this problem was aroused especially by his observations of Mr. Van Someren would doubtless emphasize the impor- tance of insalivation as a means of controlling the appetite and thereby regulating the consumption of food in harmony mth the real needs of the body, it is of primary importance for the physiologist and for mankind to know definitely how far it is possible to reduce the intake of food with perfect safety and without loss of that strength, mental and physical, vigor, and endurance which are characteristic of good health.
Please do not assume that a book's appearance in Google Book Search means it can be used in any manner anywhere in the world. Fletcher and the marked physiological economy the latter was able to practice, not only without detriment, but apparently with great gain to the body as regards strength, vigor, and endurance, coupled with an apparent resistance to disease. Further, it is equally plain that if there is possible gain to the body from a practice of physiological economy in diet, we should know how far this can be accomplished by simple restriction in the amount of food without complicating the problem by other factors. In planning the conduct of this series of experiments the writer has clearly recognized that, while it may be possible, as previous experiments have shown, to maintain body equilib- rium and nitrogen equilibrium on a low proteid diet for a brief period, this fact does not, as Munk has previously pointed out, by any means establish the view that such a diet will prove efl Scient in maintaining equilibrium for a long period, or that bodily strength and vigor can be kept up and the proper resistance to disease secured. 1 " , ^ 890 , 1032 5.60 0.358 0.78 1 » 420 1030 h.m * . Copyright infringement liability can be quite severe. pibbctob of thb bhbffibld scibwtific school of tale uniybbsitt and pbofb8sob of phtsiolooioal chbmi8tby ; mflmbbb of thb national acadbmt of 8cibncbs ; pbe8idbnt of thb ambbican physiological society ; membkb of thb ambbican philosophical society, bto. Hence, it seemed 2 18 PHYSIOLOGICAL ECONOMY IX XUTRITION necessaiy to so anmnge the expenineiits that they should con- tiniie not for a few days or weeks meiely, bat through months and yearsw Further, it is veiy questiona Ue whether the re- stricted diet (restiicted in Tariety ) frequently made use of for cou Yenience in ofdinaiy metabolism experiments is well adapted for bringing out the best nesulis. B09 0.00 1 u 827 1030 4.65 0,825 Ul tt J ^ SOO 1027 5J6 0.340 1.01 1 1* 420 1020 6.66 ♦ » » » 11 , ^ mo 1030 4.84 • . » * 1 ^ 295 1020 4.32 0.201 0.82 1 » , , 446 1020 &27 . About Google Book Search Google's mission is to organize the world's information and to make it universally accessible and useful. Hence, it was decided to avoid so far as possible any monotony of diet, giving due rec- ognition to the psychical Influences liable to affect secretion, digestion, etc^ so admirably worked out fay Pawlow in his classical experiments on these subjects : Influences which are unquestiona Uy of great importance in controlling and modi- fying, in some measuie at leasts the nutritive changes in the body. Nevertheless, this work is expensive, so in order to keep providing this resource, we have taken steps to prevent abuse by commercial parties, including placing technical restrictions on automated querying. With proteid foods, on the other hand, the story is quite dif Fei^nt. We also ask that you: Make non-commercial use of the files We designed Google Book Search for use by individuals, and we request that you use these files for personal, non-commercial purposes. These substances, when oxidized, yield a row of crystalline nitrogenous products which ulti- mately pass out of the body through the kidneys. Refrain from automated querying Do not send automated queries of any sort to Google's system: If you are conducting research on machine translation, optical character recognition or other areas where access to a large amount of text is helpful, please contact us. In addi- tion, the War Department of the United States met in large measure the expense of maintaining at New Haven the Detach- ment of Volunteers from the Hospital Corps of the United States Army, detailed here through the courtesy of Surgeon- General Robert Maitland O'Reilly. Prior to their excretion, however, these products — fi^quently spoken of aa toxins — float about tlirough the Ixnly and may exercise more or less of a deleterious influence upon the system, or, being temixmirily de[X)sited, may exert some specific or local influ- ence that ctdb for their upeedy removal.