NA TORE 



41 



THURSDAY, MARCH 15, 1917. 



HUNGER AND APPETITE. 

 (i) The Control of Hunger in Health and 



Disease. By Anton Julius Carlson. Pp. vii + 



319. (Chicago: University of Chicago Press; 



Cambridge : At the University Press, 1916.) 



Price 95. net. 

 (2) Food and Health: An Elementary Text-hook 



of Home Making. By Prof. Helen Kinne and 

 i. Anna M. Cooley. Pp. vi + 312. (The Home- 

 r Making Series.) (New York : The Macmillan 



Co.; London: Macmillan and Co., Ltd., 1916.) 



Price 35. net. 



(i) pROF. CARLSON gives, in this volume, 

 -*- a general account of the work done, 

 chiefly in his laboratory, on the physiology of 

 hunger and some related questions. He was for- 

 tunate to have as subject of experiment a man 

 who possessed a gastric fistula, made in conse- 

 quence of an oesophageal stricture when he was 

 a boy. Experiments were also made on Prof. 

 Carlson himself and other normal subjects, as 

 well as on dogs and lower animals. 



The net result of the investigation is to show 

 that the sensation of hunger is due to a periodic 

 series of rhythmic contractions, which take place 

 in the stomach when empty. Haller had sug- 

 gested this cause, but thought that the sensation 

 was produced by the rubbing together of folds of 

 the mucous membrane. Prof. Carlson shows that 

 the sensation has its origin in receptors in the 

 muscle substance itself. The contractions are 

 started in the stomach, although their rhythm is 

 slightly altered after the stomach is separated 

 from the central nervous system. When food is 

 taken the hunger contractions cease for a few 

 minutes, and then the movements of digestion 

 begin. These differ from the hunger contrac- 

 tions, being primarily concerned with the pyloric 

 end, whereas the latter are initiated at the 

 cardiac end and pass as peristaltic waves over 

 the whole stomach. It would seem that the only 

 satisfactory explanation oT the digestion contrac- 

 tions is that they are brought about by the 

 central nervous system, the hunger contractions 

 being inhibited for the purpose. This inhibition 

 can be produced by sensations of taste, or by the 

 presence in the stomach of water, gastric juice, 

 acid, alkali, oil, and other things, or in the in- 

 testine of gastric juice, acid, or alkali. It is in- 

 teresting to note that alcohol inhibits hunger, 

 while it may increase appetite. Appyetite, in fact, 

 is quite different from hunger, being rather a 

 mental anticipation of pleasant sensations to 

 come. It is, however, more complex than this, 

 as the discussion in Prof. Carlson's book shows. 

 We know that appetite may be present without 

 hunger, and the experience of fasting men is that 

 hunger may be present without appetite. 



The nerves that convey the afferent impulses 

 produced by the hunger contractions are the vagi. 

 As already stated, these contractions are not set 

 XO. 2472, VOL. 99] 



mto action by any stimuli from the outside, 

 although they can be thus inhibited. The 

 channels of inhibition appear to be chiefly through 

 the splanchnic nerves, but central inhibition of 

 the tone of the vagus centre also plays a part. 

 We find, therefore, a further case of reciprocal 

 innervation of the kind described by the reviewer 

 in vaso-motor reflexes. 



Various other questions are elucidated inci- 

 dentally. The sensibility of the gastric mucous 

 membrane to heat and cold is shown to be a true 

 one, and Head's statement as to its protopathic 

 nature is confirmed. 



The want of food, even in protozoa and plants, 

 is manifested by increased excitability and rest- 

 lessness. In animals this state induces them to 

 take food, because they have learned that food 

 abolishes the feeling. 



The book concludes with observations on the 

 secretion and the chemical properties of human 

 gastric juice, and with the discussion of hunger 

 and appetite in disease. As a practical general 

 conclusion we may note that the physiological way 

 of increasing hunger and appetite is moderation 

 in the amount of food taken, or increasing the 

 utilisation of food by outdoor living, fresh air, 

 cold baths, and muscular exercise. 



The book is a very valuable and interesting 

 account of a somewhat neglected branch of 

 physiology. 



(2) This manual is of a different nature. Al- 

 though intended primarily for use in schools, it 

 contains a mass of useful information for all con- 

 cerned with occupations in the home. It is chiefly 

 concerned with the preparation of food, but in- 

 cludes instructions for its preservation, and also 

 for the raising and selling of poultn,- and so on. 

 The making and properties of bread are described 

 in considerable detail. 



The physiological facts are correctly given, and 

 the explanation of the energy value of food and 

 the unit in which it is expressed, the Calorie, is 

 particularly well done. There are, however, one 

 or two surprising omissions. No reference is 

 made to the "accessory factors" of food, or to 

 the misuse of alcohol, although we have a warning 

 against the far less serious misuse of tea and 

 coffee. Perhaps the alcohol question is not so 

 pressing in the United States as with us. 



Both books are well provided with illustrations, 

 and contain indexes and references to literature 

 for those who wish to follow up the subject in 

 more detail. Many otherwise excellent works lose 

 much of their value owing to the absence of one 

 or other of these indispensable components. 



W. M. Bayliss. 



THEORETICAL AND PRACTICAL PHYSICS. 



(i) A Text-book of Physics. Edited by A. Wilmer 

 Duff. Fourth edition, revised. Pp. xiv + 692. 

 (London : J. and A. Churchill, 1916.) Price 

 1 05. 6d. net. 



(2) Practical Experiments in Heat. Pp. viii - 123. 



D 



