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NA TURE 



[December 2, 1922 



rubber ; as a possible competitor of the natural variety 

 its future appears hopeless. More plantation rubber is 

 being produced than the world at present requires, or is 

 likely to require for some time to come. At the same 

 time, the investigations which have led to the synthesis 

 of rubber, or of rubber-like substances, have' great 

 theoretical value, and have shed much light on the 

 true nature and chemical constitution of this most 

 remarkable substance. 



Forward Progression. 



Gaseous Exchange and Physiological Requirements for 

 Level and Grade Walking. By Henry Monmouth 

 Smith. (Publication No. 309.) Pp. viii + 310. 

 (Washington: Carnegie Institution, 1922.) 6 dollars. 



FORWARD progression, perhaps the form of 

 muscular activity most commonly engaged in 

 by the average human being, is, both in its anatomical 

 and physiological aspects, one of extraordinary com- 

 plexity. The work of Marey, Carlet, Braune and 

 Fischer has thrown much light on the actual movement 

 of the body and legs during the forward movement, 

 and the researches of Zuntz and Schumburg, Durig, 

 Douglas, Benedict and Murschhauser, and others have 

 helped towards the elucidation of the metabolism and 

 energy expenditure of the movement. A number of 

 problems which have emerged from the previous in- 

 vestigations still remain unsolved ; some of these 

 questions are discussed, and in part elucidated, in this 

 new volume from the Carnegie Institution's Nutrition 

 Laboratory at Boston. 



This book forms the natural sequel to the work of 

 Benedict and Murschhauser. These workers dealt with 

 the changes in the metabolism, the cost and the 

 efficiency of the human body during horizontal walking. 

 Monmouth Smith's work, although ostensibly it is 

 meant to deal principally with " grade " walking, 

 contains much new data on horizontal walking, more 

 especially as regards the influence of the movement 

 and change of position on the blood pressure, pulse 

 and temperature. The effect of horizontal walking 

 on the blood pressure is not great ; as regards the pulse 

 rate, one of the most striking features is the great 

 variation found in the same subject under apparently 

 identical conditions. In connexion with the rectal 

 temperature several interesting facts emerge : (a) there 

 is a definite lag in the rise of temperature which occurs 

 in changing from standing to walking ; (b) except at the 

 higher rates the effect of the rate of walking is small ; 

 and (c) the maximum increase at any speed less than 

 100 metres per minute does not exceed 0-5° C. (without 

 taking into consideration the duration of the exercise). 

 NO. 2770, VOL. I IO] 



Many new observations have also been made on the 

 " step-lift." A slightly lower value for the cost of this 

 operation than that of previous workers was found. 

 A slightly lower value than that commonly accepted 

 was also found for the energy cost per horizontal 

 kilogrammetre. 



In the grade - walking experiments a preliminary 

 series of experiments were made on the influence of the 

 mouthpiece on the breathing of the subject. These 

 tests are of considerable technical interest. The 

 general result is that unless the preliminary period of 

 breathing with the mouthpiece in position be of 

 sufficient duration, the accuracy of the determination 

 of the respiratory quotient is endangered. 



A large number of observations were also made on 

 the influence of grade walking, in addition to the 

 determination of the energy cost, on the blood pressure, 

 pulse, pulmonary ventilation, and temperature. Those 

 on the temperature are particularly interesting. It 

 was found, for example, that the temperature increase 

 was not always the same for the same amount of work, 

 although, as might be expected, a higher temperature 

 and a greater increase over normal were usually 

 observed when the work and the metabolism were 

 greatest. The maximum total increase, when the 

 work done was heavy, was between 1-5° C. and 2° C. 

 A number of very interesting experiments on the rate 

 of the fall of the rectal temperature after the cessation 

 of work are recorded. In one experiment at least it 

 was very rapid, 1-14° C. in twelve minutes, or 0-09° C. 

 per minute. On the other hand, if observations were 

 continued, the rectal temperature was found to approxi- 

 mate normal pre-work temperature only about two 

 hours after the cessation of work. 



The Nature of Science. 



What is Science? By Dr. Norman Campbell. Pp. 

 ix + 186. (London: Methuen and Co., Ltd., 1921.) 

 55. net. 



WHAT is Science ? " is a question that may be 

 answered in as many ways as " What is 

 Truth ? ", and much depends on the questioner. In this 

 case the original questioner was apparently an audience 

 drawn from the Workers' Educational Association. 

 Fifty or more years ago the worker was all agog for 

 science ; now, it appears, he either shoulders it aside 

 as too academic for practical use, or rejects it as the 

 " stone " of vocational education proffered instead of 

 the " bread " of culture. The worker, in this limited 

 sense, is not alone in misapprehending what is meant 

 by " science," for the public at large, as recent years 

 have given abundant proof, often blames it for sins 



