194 



NA TURE 



[JiAN.UA«Y 2i 1902; 



I'looths of a second. The mean of the observations 

 made this quotient =173 with a 2: kg. load, rsS with 

 37 kg., and \^^,^^ with 31 kg., while the lowest quotient of 



- recorded during rest was 1S8 and the highest 3'2S. 



The effect of heavy marches on the systole and diastole 

 of the heart was, therefore, as the authors e.xpress it, 

 undoubted. They attribute the result to fatigue of the 

 cardiac muscle and consider that, if the load is raised 

 beyond 31 kg., permanent damage to the heart may 

 result. They also noted that the pulse increased to 140 

 and 150 beats per minute and that dicrotism became 



marked as the quotient of — approached unity. 



Another important and unexpected result was that in a 

 series of eighty-nine observations the cardiac area of 

 dulness showed marked increase in si.xty-four and the 

 hepatic area in si.\ty-seven instances after the march. 

 This increase was noted in 56 per cent, of the observa- 

 tions after a march with 22 kg., in 704 per cent, with 

 27 kg. and in S7'5 per cent, with 31 kg. 



Still more important is the observation that the increase 

 in the area of dulness was due to dilatation of the right 

 and not of the left side of the heart, and that it is pro- 

 duced by a general stagnation of the venous circulation. 

 The authors designate the phenomenon " march dilata- 

 tion of the right side of the heart.'' 



These observations on the cardiac function are new 

 and well worth noting. They have special significance 

 for the military medical officer, as they throw a new light 

 on the condition known as "disordered action of the 

 heart," which is a common sequel of military training and 

 the cause of a considerable amount of invaliding in the 

 British Army. 



The observations on other organs and functions did not 

 produce quite such interesting or positive results. The 

 specific gravity of the blood was only increased by '006 and 

 the red blood corpuscles by 9 per cent, after the heaviest 

 march. An apparent increase of 43 per cent, in the white 

 corpuscles was due to polynuclear cells being carried into 

 the circulation from the walls of the larger veins, in conse- 

 quence of increased cardiac action ; but the blood 

 resumed its normal condition on the day following the 

 march. 



The vital capacity of the lungs was studied by means of 

 an experimental gas meter, into which a number of ex- 

 pirations was made in succession, and the volume indi- 

 cating vital capacity determined by dividing the total 

 record by the number of expirations. This was considered 

 more accurate than records given by Hutchinson's spiro- 

 meter. Sixty-nine observations were made during marches 

 with loads and eighty-nine during marches without loads. 

 The practical result was that, up to a certain point, the 

 graduated training of the soldier increased his vital 

 capacity, but that a marked diminution occurred in 

 marches with the heaviest loads, this serious result 

 being associated with the dilatation of the heart and liver 

 and the venous stagnation already noted. Another prac- 

 tical observation was that the increase in frequency of 

 respiration, which is invariably associated with exercise, 

 gradually falls to normal during halts, but that when 

 dilatation of the right side of the heart had become well 

 NO. 1679, VOL. 65] 



marked, this increase remained as high as 40 per cent,' 

 above the normal even after a halt of 30 minutes. The- 

 authors conclude that frequency of respiration exceeding 

 28 per minute, or 75 per cent, increase on the normal^ 

 with a gradual fall to 30 per cent, above normal after' a. 

 quarter of an hour's halt, is the limit which can be borne'- 

 by a soldier of average strength without breakdown^ 



The observations on the effect of the marches on body 

 temperature are comparatively brief, but the subject of' 

 the regulation of heat and the calorific value of the work- 

 done forms a complicated series^ of calculations and- 

 experiments introduced into the chapters which' are- 

 devoted to the study of metabolism. The authors- 

 estimate that the heat production of the work done in- 

 marching is sufficient to raise the body temperature 1° C. 

 in 87 minutes. In the direct observations there wa& an. 

 actual increase of temperature of 1 ' to i '5 C. only, after* 

 the heaviest marches. As the surface cooling resulting: 

 from the evaporation of sensible and insensible perspira- 

 tion plays so important a part in maintaining heatr 

 equilibrium, the authors rightly emphasise the importance- 

 of attention being paid to the material and nature of the- 

 soldiers' clothing with a view to avoiding interference withi 

 this function of the skin. 



Experiments on the influei>ce of the marches on the- 

 nervous system and on muscles were unsatisfactory.. 

 Observations were made on the "reaction period," and 

 ergographic tracings were taken with Mosso's apparatus.. 

 The results in both cases were inconclusive and conflict- 

 ing, weather, individual disposition, auto-suggestion, alt 

 helping to bring this about. Ar» attempt was also made 

 to estimate the effects of the marches on the nervous- 

 system by some ingenious memory tests, but they were 

 so influenced by the drowsiness consequent on the early 

 morning start that the after results were quite in- 

 conclusive. 



Some interesting facts are recorded in connection with 

 the renal function. Notwithstanding the great loss of 

 water by perspiration, there was no increase in the 

 specific gravity of the urine. Thus the average specific 

 gravity in 150 observations before the march was lo23'6y 

 and after the march 10217. This convinced the authors 

 that marching has a diuretic effect, and they recall similar 

 observations by Oertel and Henschen. Their observa- 

 tions on albumin in the urine are also contrary to the 

 general impression, an impression no doubt derived from 

 the observations of .Albu and of Macfarlane, that during 

 hard physical exercise transient albuminuria occurs. 

 Zuntz and Schumburg found nothing of the kind amongst 

 their five students, and they point out that Benedicenti 

 had made similar observations on soldiers. 



The series of observations and experiments on meta- 

 bolism includes analysis of nitrogenous waste, respiratory 

 changes, calorific value of the work performed, and the 

 regulation of the body temperature. The observations 

 are of an elaborate and complicated character, and only 

 two of the fi\e students were submitted to experiment. 

 The chief practical results may be briefly noted. 



The elimination of nitrogenous products both by the 

 skin and kidneys was not markedly influenced by the 

 marches. When increase did occur, it occurred on the 

 day following the march, and not during or immediately 



