PHYSIOLOGY. 



677 



ing to the experimenters, the resulting fatigue 

 is twofold the fatigue of nervous failure and 

 the fatigue of muscular failure. In certain cases 

 the fatigue comes from the collapse of the mus- 

 cular tissue only, while in others it happens that 

 the brain suspends the supplies necessary to 

 keep the muscles active. Some experiments 

 showed that if a fatigued finger bore a weight 

 v/ith difficulty, the moment the weight was 

 withdrawn the finger would recoil backward 

 with force, a proof that while the muscular 

 energy had run out, the nervous energy was 

 striving to compensate it by imposing on the 

 muscle an effort much stronger than necessary. 

 Other experiments were made on the influence 

 of the weight to be lifted, as well as on that of 

 anaemia. When the arteries of the arm under 

 experiment were constricted or it was made 

 wholly bloodless, the muscle was found capa- 

 ble of continuous effort, but only through nerv- 

 ous excitation ; and it was observed how the 

 muscular energy revived gradually as the blood 

 returned into the arm. The effects of fasting, 

 and the duration of the time that must elapse 

 after the taking of food to re-establish the con- 

 ditions of normal muscular labor ; the influence 

 of respiration and of those processes of train- 

 ing whereby the organism is inured to bear the 

 heaviest fatigue ; and the influence of certain 

 aliments in the production of labor, were the 

 subjects of further series of investigations. On 

 the last point the induction was confirmed by 

 novel methods that alcohol, instead of aug- 

 menting muscular energy, positively dimin- 

 ishes it. 



The influence of gases on the intestinal move- 

 ments has been investigated by Bokai, who 

 finds that while such inert gases as hydrogen 

 and nitrogen are without effect either in in- 

 ducing or allaying persistaltic contractions, 

 others notably carbonic acid, carbureted 

 hydrogen, and sulphureted hydrogen in- 

 crease these movements to a very marked de- 

 gree. The violent persistalsis induced by the 

 injection of carbonic acid into any portion of 

 the intestine can at once be stopped by passing 

 a stream of oxygen into the part, as well as 

 by the injection of lime-water. The mere ab- 

 sence of oxygen has the same effect as the pres- 

 ence of carbonic acid, in both cases the action 

 being entirely a peripheral one, limited to the 

 portion of the intestine affected. Carbureted 

 hydrogen or marsh gas and sulphureted hydro- 

 gen also produce marked peristaltic movements 

 when injected into the intestine, which can 

 similarly be allayed, although not completely, 

 by the subsequent injection of oxygen. These 

 observations serve to throw some light on the 

 mode of action of sulphur as a purgative, and 

 of subnitrate of bismuth as an astringent and 

 sedative. The latter substance is found to be 

 a useful remedy, in cases of diarrhoea, from its 

 power of combining with sulphureted hydro- 

 gen and with other gases developed in the in- 

 testinal tract as the result of fermentation and 

 decomposition. 



The action of hot and cold water on the 

 muscular walls of the uterus and on the blood- 

 vessels has been partially investigated by Dr. 

 Milne Murray, of Edinburgh. The main re- 

 sults arrived at after experimenting with three 

 grades of temperature, viz. : Water at from 32 

 F. to 60 F., from 60 F. to 110 F., and from 

 110 F. to 120 F., are: 1. That the applica- 

 tion of the low temperature water produces 

 a marked latent period ; a slow contraction 

 period of from one to five minutes; and a 

 period of a gradual relaxation a very impor- 

 tant one for arrest of haemorrhage lasting for 

 about three times the contraction period, 

 namely, for from three to fifteen minutes; 2. 

 That the application of water at the high tem- 

 perature produces a very short latent period, 

 or even obliterates it ; the contraction period 

 developes rapidly (thirty-five seconds) ; and 

 the period of gradual relaxation occupies from 

 six to fifteen minutes. In the case of the arteries 

 water at temperatures of from 110 F. to 120 

 F., constricts blood-vessels and arrests haemor- 

 rhage from small arteries ; at temperatures of 

 from 60 F. to 100 F. it dilates small vessels, 

 and promotes haemorrhage ; at temperatures of 

 from 30 F. to 50 F. it checks haemorrhage by 

 temporarily constricting the vessels; but this 

 is followed by intense reaction. These experi- 

 ments, though needing to be repeated with 

 greater care for scientific purposes, give results 

 of great practical value to those who have to 

 deal with the arrest of haemorrhage. 



A new method and apparatus for obtaining 

 graphic records of the various kinds of move- 

 ments of the hand and its parts and for enu- 

 merating such movements and their combina- 

 tions have been devised by Dr. Francis War- 

 ner. The apparatus consists of an arrangement 

 of India-rubber tubes to be fitted upon the fin- 

 gers or moving parts, with which adaptations 

 for electrical registration are so connected that 

 every movement is correspondingly marked. 

 By the method of investigation which this ap- 

 paratus is intended to assist, tracings may be 

 obtained of muscular movements due to the 

 action of the central nerve-mechanism, from 

 which some evidence can be derived concern- 

 ing the effects of brain action in its different 

 parts as indicated by muscular movements. 

 Thus, in infancy, spontaneous movements of 

 the fingers are usual while the child is awake 

 and spontaneous muscular movements are oc- 

 curring all over the body. These movements 

 can be arrested by light and probably by sound. 

 In studying the mental development of infants 

 we mainly judge of the rapidity and stage of 

 their growth by observing the amount, kind, 

 and co-ordination of their motions. Tracings 

 could be given of these motions; separate 

 movements might be enumerated ; and possi- 

 bly we might enumerate the special combina- 

 tions of movement, showing whether such 

 combinations occur more commonly at one 

 time than at another, or more commonly under 

 any particular set of circumstances. 



