December 15, 1898] 



NA TURE 



151 



^luring and immediately after exercise the amount 



' > in the blood was increased, and amount of COo 



diminished as compared with their amounts at rest. 



, Thev further concluded that during muscular exercise 



the contracting muscle poured into the blood sub- 



i stances the chemical nature of which was unknown, but 



which exerted a stimulating action on the medullary 



I repiratory centre. In this phenomenon, according to 



'them, neither pulmonary nor muscular centripetal nerves 



' play anv roU-. This latter dictum has been disputed by 



, Filehne and Kionka {Fjlugcrs Archives, Ixii. 96, p. 201}, 



who hypothecate the existence of afferent nerves in the 



\ lung and muscles, which are sensitive to CO^. production 



and are stimulated thereby. The main result of Zuntz 



j and Geppert's work was not challenged by them, and still 



i stands. In a later monograph Zuntz and Cieppert main- 



j tain, and apparently correctly, their former work in its 



I' entirety. 



f This increased respiratory activity is within certain 

 ' limits from a therapeutic standpoint a desideratum, as 

 pulmonary resistance is thercb\- diminished, and the 

 general circulation and flow of lymph accelerated. 

 \ In order to produce this salutary effect the respiration 

 ) during exercise should be easy and full, and anything 

 '\ approaching effort, with its usual concomitant, closure 

 , of the glottis, should be avoided. 



In this connection Dr. ("ampbell's recent book is inter- 



I estiiig and useful. We cannot agree with the view ex- 



I pressed on p. 1 11, with regard to the causation of the 



I dyspniLa attending exercise. The author at the close of 



his book gives a list of respiratory exercises calculated 



I to attain certain ends. Dr. Campbell has produced an 



I instructive and interesting monograph, and we shall be 



pleased to welcome his promised work on the mechanical 



treatment of heart disease. 



Concerning the effect of muscular exercise upon the 

 circulatory system, we have a very abundant literature 

 to rc\ lew, both physiological and medical. The recent 

 development which this branch of therapeutics has taken, 

 as exemplified by the thousands of visitors flocking to 

 Nauheim, and the \arious mechanic, or manual gym- 

 nastic institutes, and the still larger numbers treated 

 at their own homes, render the subject of considerable 

 interest. The effects of the contraction of a muscle 

 or group of muscles upon the circulation may be 

 divided into local and general. The local effects, or 

 the effect of its contraction upon the circulation through 

 a muscle, was first investigated by Ludwig and his 

 pupils, Sczelkow, Sadler and C.askell. Some of Sadler's 

 (Luifu'tjr's Arheiten, 1869, p. 77) results have a direct 

 bearing upon resistance exercises as practised at the 

 present day, since he studicil the circulation through a 

 group of muscles which were thrown into contraction, 

 but were at the same time prevented from becoming 

 shortened. He found that, as in the case of muscles 

 contracting under ordinary circumstances, more blood 

 passed through them than in the condition of rest. He 

 also found that more blood passed through the contract- 

 ing muscles when they were prevented from becoming 

 shortened, than when they were allowed to do so. 



Ciaskell's {Liiih^'ia^'s Aiihitm, 1877, p. 45) experiments 

 showed that the maximum flow occurred either at the end 

 of a long contraction (tetanus), or directly after the ces- 

 sation of a contraction. In all these experiments the 

 e.xcitant was electric stimulation. In the case of exercise 

 in the liv ing animal the excitant is either volitional or 

 reflex. The results, however, of Cheauveau and Kauf- 

 mann Arcliircs dc Pliys., 1892, p. 279), who worked on 

 the masseter of the horse during mastication, and in the i 

 main confirmed the above results, showed that the 

 artificial nature of the excitant in Ludwig's experiments 

 made no appreciable difterence. Mosso' found that the 



1 '■ Sulle Varia/ioni loc.ili Jel poljo nel ante-braccio del uomo." Torino, 



NO. 1520, VOL. 59] 



[ volume of an arm as measured phlethysmographicallyin- 



I creased immediately after contraction of the flexors. 



I Some experiments I made conjointly with Dr. Lauder 



{ Brunton ' showed that the amplitude of the pulsation of 



the arteries contained in the gastrocnemius increased 



considerably immediately after contraction of this muscle. 



The tracing showed that in addition to the arteries being 



dilated immediately after contraction they were rela- 



I tively fuller of blood. 



These results, obtained by tlifterent methods and by 

 several observers, seem clearly to indicate that one of the 

 local circulatory effects of muscular exercise is a dilata- 

 tion of the vessels of the corresponding muscular area ; 

 or, in other words, a lessening of the resistance to the 

 flow of blood through the muscles. In view of the re- 

 laxation of the antagonistic muscles which apparently 

 accompanies the contraction of any group of muscles, it 

 would be interesting to see what, if any, changes occur in 

 the vessels of these relaxing muscles. If a dilatation 

 occurs here also, as seems A priori probable, the vascular 

 area aftected would be considerably increased, and then 

 the eftcct on the general circulation would be magnified. 

 If we turn from the local circulatory eflects of muscular 

 contraction to the eflects produced on the general cir- 

 culation by the contraction of a group of muscles, we 

 shall find in the first place that a determining factor of 

 the greatest importance is the amount of exercise ; and 

 this is best measured by the degree to which the respira- 

 tion is affected. The results of former observers, Marey 

 (,"> La Circulation du Sang," 1S81, 343). Oertel,'- von Basch, 

 and others, have been entirely confirmed by those of 

 more recent investigators, viz. Hallion and Comte (C A'. 

 Soi. lie ISioit\iiie, x. serie, iii. 906), Bloch, Mosso (Der 

 Mensch auf den Hochalpen Leipsig, 1899), Brunton 

 and myself {loc. a'/.), Zuntz and Hagemann {Deit/seh 

 Med. li'oc/i, 1892), Taugl unA ZmWi (rjlut^er^s Arc/iiv., 

 Ixx. 544, 1898), and Kaufmann (Arc/iii-es ile P/iys., 

 serie 5, t. iv. p. 493). Zuntz and his collaborators are 

 evidently unaware of the work of Mosso and his pupils, 

 and of Brunton's and my own paper. 



The results of Zuntz and his collaborators showed that 

 in the horse a gentle walk was accompanied by a fall in 

 blood pressure amounting to about one-twelfth. In the 

 case of dogs, gentle exercise was accompanied by a 

 slight rise in blood pressure amounting to one-twelfth or 

 one-tenth, whereas violent exercise rapidly caused a 

 doubling of the blood pressure in the carotid. The 

 experiments made in Mosso's laboratory on man, in- 

 cluding those contained in l>runton's and my own paper, 

 confirm the above results obtained upon animals. How- 

 ever gentle the exercise, an increase, sometimes veryslight 

 in blood pressure, occurs ; this, however, sometimes during 

 exercise, invariably after it, is followed by a fall, which 

 continues for some time after the exercise has ceased. 

 If the exercise is violent the accompanying rise in blood 

 pressure is considerable— one-sixth to one-eighth, and 

 this high pressure is continued so long as the exercise 

 lasts, the pressure gradually returning to its former level; 

 this, in some cases, taking two hours or more. .\\\ observ- 

 ations upon the blood pressure in man directly after 

 exercise more or less severe, which have been sufficiently 

 numerous, confirm these results (see "Oertel," /or. a'/.). 

 These experiments are of interest from a therapeutic 

 standpoint, in that they show that it is possible to obtain 

 the beneficial eflects of exercise at the expense of a very 

 slight extra strain upon the heart. 



A question at the present time of considerable interest 

 is, how are the cardio-vascular results which follow exer- 

 cise brought about ? .^re we to assume that they are 

 central, and are produced by the action of substances of 



1 " Remarks on the effect of Resistance E: 

 general." {liritish Medical JoiirKat, October to, 



- '' Handbuch der allgemeiner Therapie de 

 Leipzig, 1S91. 



iSp7.) 



local and 



Kreislaufs Stornngen." 



