680 



PI1Y>1<>! 



continue to contract. <M, slowing the heart by 



.tat ion t|u> rhythmical contra, t ion- of i he 



isolated piece may U- \\nti-hi--l without difficulty. 



rhythm, then,' differs from that of tin- remain- 



tin- heart. It follows that tlir iii\thm: 



f tin- isolated maiiiiiialiaii np-\ aiv not 



.In.- to changes in the bUid during it.- deHbrina- 



In other e\|*-rimi-nts Mr. Porter found tl> > 



hrart. or any part of it. from 

 filiation, i- ... mi. 1 b\ feeding tli.- part 

 with deflbriimtcd dog's I'lo.nl through the cor 

 artery. When an isolated part of a dog't OI 



In- ant!.. :. i- fed through the 



ry art. -r\. tin- Mow from the \rin- app 



. than during diastole. In an 



; ntcd heart supplied with MINN! at a constant 

 pressure through the coronary arteries a pulse -yn- 



.us with the systole was observed in tin- -u- 



::l auricular veins In-fore and after their roii- 



n with the coroiiarv -inn- was severed. A 

 similar but much less marked pulse could le dem- 

 onstrated in the 1-oroiiary arteries. When a 

 on li. "f a ventricle in m'fii in the living 



animal was inci-ed and the heart slowed by vagus 

 .it ion the flow from the cut vein was much in- 

 creased during ventricular systole. These ob-er\a- 

 i as showing that t he coiit rac- 

 tion of the cardiac muscle compresses the 

 and to a less extent the arteries in the Mil-stance 

 of the heart. The systole must therefore facilitate 

 the circulation through the heart muscle. The 

 minimum manometer failed to show a negative 

 pressure in the coronary arteries. The ventricle 

 acts on the coronary circulation as a force pump. 

 and n<>t to any noticeaiiie | -action pump. 



In an experiment liy F. II. Pratt in which the 

 auricles of the cat's heart wen- tied off from the 

 ventricles, both coronary arteries were ligated. and 

 the ventricle was fed. the ventricle beg-in to con- 

 tract rhythmically, slowly at first, but gradually 

 attaining the normal rate. The blood within the 

 ventricle and in the veins became venous, and if 

 contractions were to IM> sustained had to be period- 

 ically renewed. If a vein was opened a -mall but 

 steady outflow of blood occurred. Increasing the 

 load beyond that furnished by a blood column of 

 " inches lowered the force of contraction. Con- 

 tractile activity could le kept up by this method 

 for some time. These experiment! we're interpreted 

 as indicating plainly a nutritive phenomenon: the 

 blood becomes reduced, and must be removed in 

 order to sustain contraction. Proof is adduced 

 that the contra not due to mere nicehan- 



ical stimulus. A genuine circulation is shown to 

 exist between the ventricular cavity flnd the 

 narv veins through the vessels of Thebcsius. It is 

 added that the possibility of a nutrition from the 

 direct may serve to explain some cases 

 in which thrombosis or other stoppage of the coro- 

 nary arteries has failed to destroy tne normal ac- 

 tivity of the heart. 



change* of the pulse at different hours of the 

 day and the influence of muscular and of mental 

 work mx.n the capillary circulation have been 

 studied by A. P.inet and J. Courtier. Kx|N-rr 

 concerning the first problem are dc-cribcd as hav- 

 ing been made uj-on three nubje. , gave 



marked indications in summer than in winter. 



when the temperature was t The 



- of a meal appeared to be represented in the 

 capillary p in increase of the pul-ation or 

 an accentuation of tin- dicrotism. For the indi- 

 vidual, the diagram of the pulse may be influenced 

 for the moment or for a j*-riod of time by the state 

 of health, phy-ical -ntal labor, the emo- 

 tions, or overwork ; but through ail these accidental 



i. -n-. taking the pul-e hour by Unur after tho 

 meal, the direction, the order of changes in the form 

 of the |ni!- , i mi, 'lit is cited 

 to show that the form of the pOU6 (tracing) indi- 



the organism ratlin- than 

 the local condition of the hand. 

 il. fatiguing mn-ciilar 



ningofthe diri-oti-m. a blunting of the pul- 

 ;. a tendency to a displacement of the dicrotisin 



toward the point <.f it. A general, moderate nni-- 



cular i- instance, di-pre-x.-s and 



accentuates the dicroti-m. and intensifies tin- pul- 



(ieneral. exce ively fatiguing mn-ciilar 



rovokei a peakeoln dierotism. 



without displacement toward the point of the pul-a- 

 tion. An energetic, brief mental effort i- found to 

 pndu-e excitation of the function-. DStlic- 



tion. acceleration of the heart, and respirati* i 

 followed liy a very -light -lowing of these function-; 

 and in -oiiie subject-, weakening of the dicrot i-m. 

 Mental labor lasting several hours while th- 

 is relatively still produces slowing of the hear 

 a diminution of the peripheric capillary circulation. 

 A-kingifany relation can lie e-iabli-hed b. 

 the elf eels of" mental and those of physical labor on 

 the capillary circulation, the author- remark that 

 mental labor may be regarded as an excitation of 

 the nervous system, in which point it resembles, 

 phy-ical labor, and produces accelerat jon of n-pira- 

 tio'nand of the heart, as muscular labor do, 



is therefore possible, in View of the physical etTects. 



to comnare a mental calculation to the;.. 

 ing a dynanioiiietcr. Further, the capillary circu- 

 lation is often modified in the same way by pi, . 



-e and mental work. A passing effect -i'milar 

 to that of walking in lessening t he pulse and B 

 tuating the dicrot i-m occur- at t he beginning of a 

 mental work. Further, a fatiguing phy-ical effort 

 weakens the dicroti-m : and so a mental work with 

 some subjects may bring on a weakening of the cap- 

 illary pul-ation. " On the other hand, tin- differ- 

 ences between phy-ical and mental work are nu- 

 merous. The excitation of the heart i- much inn 

 considerable and the acceleration of respiration i- 

 much greater under the influence of physical effort. 

 The amplitude of re-pi rat ion i- augmented during 

 muscular exercise, while it becomes more superficial 

 during mental work. We should, moreover, recol- 

 lect that prolonged mental work brings on an 

 attenuation of the peripheric capillary circulation. 

 Phy-ical and mental effort constitute excitations of 

 the' nervous sy-tem ; but the excitation of mental 

 work i- much inferior in degree to that of physical 

 work, and it seems to be of another quality, a- i- 

 shown by two effects which are special to mental 

 work : the contraction of the thoracic cage and the 

 attenuation of the jieriphcric capillary circulation. 



From experiments upon the influence of emotion 

 on the heart's respiration and capillary circulation. 

 Messrs. A. P.inet and .1. Courtier find that with the 

 majority of persons every emotion produces a vaso- 

 riclioii. an acceleration of the heart and re-pi- 

 ration, and an increase in the amplitude of the 

 thoracic cage effects which are more marked as 

 the emotion i- more intense. In -..me very ran- 

 cases a painful sensation and a sad emotion have 

 produced a very slight -lowing of the heart. The 

 possibility is suggested by the observation of one 

 subject that the form of the capillary pulse (tracing, 

 changes with the Duality of the emotions. From 

 this jt mav be | MIC time to make a classi- 



fication of the emotions according to their effect on 



the form of the pul-e. 



of that subject. 



Prof. 11. Kronecker and I>r. A. Marti conclude, with 



t to the relation of cutaneous excitation and 



the formation of red blood corpuscles, that feeble 



