PHYSIOLOGY. 



759 



entered. The common salt solution should, 

 further, be disinfected beforehand by boiling, 

 and the air which penetrated into the reser- 

 voir while it was being emptied must be fil- 

 tered by means of a wadding stopper. The 

 injurious effect of too strong pressure was illus- 

 trated by a comparative experiment on two 

 rabbits. 



B. W. Richardson has made some calculations 

 of the amount of work performed by the heart 

 in a healthy adult man. By tracing the work 

 out by the minute, hour, and day, the author 

 shows that it is equal to the feat of raising 

 5 tons 4 cwt. one foot per hour, or 125 tons 

 in twenty-four hours. Turning to the mile- 

 age of the circulation, and presuming that the 

 blood is thrown out of the heart at each pulsa- 

 tion in the proportion of 69 strokes a minute, 

 and at the assumed force of 9 feet, it may be es- 

 timated to be equivalent to 207 yards per min- 

 ute, 7 miles per hour, 168 miles per day, 61,320 

 miles per year, and 5,150,880 miles in a life- 

 time of eighty-four years. The number of 

 beats of the heart in the same long life would 

 reach the grand total of 2,869,776,000. The 

 imbibition of 8 fluid ounces of alcohol adds 24 

 foot-tons to the heart's daily burden. 



Herr Holzmann sums up the following as 

 the results of his investigations of the condi- 

 tions of blood-clotting : A body called fibrino- 

 gen, belonging to the class of globulins, can be 

 obtained from horse's blood, and solutions of 

 fibrinogen neither coagulated spontaneously at 

 ordinary temperatures, nor upon dilution with 

 water ; defibrinated blood, blood serum, watery 

 extract of the albuminous coagulum, formed in 

 blood-serum by the addition of alcohol, or the 

 extract obtained from egg-albumen coagulated 

 in the same way, the putrescent fluids obtained 

 from cooked egg-albumen, and long-continued 

 passage of oxygen, all cause typical coagula- 

 tion of the solution of fibrinogen at ordinary 

 temperatures with the production of fibrin. 

 Fibrin-ferment is not peculiar to the blood, 

 but occurs among the decomposition products 

 of albumen. It is probable that fibrin is the 

 product of the oxidation of fibrinogen ; when 

 a dog is rapidly bled to death (one and a half 

 to three hours), the last portions of blood 

 drawn clot quicker than the first, though the 

 amount of fibrin does not markedly vary. 

 Venous blood clots more slower than arterial 

 blood ; suffocation delays coagulation. Curare, 

 chloral hydrate, chloroform, quinine, and sodi- 

 um carbonate also delay it. 



Respiration. Dr. Gad, reporting to the Phys- 

 iological Society of Berlin respecting his ex- 

 periments on hpemorrhagic dyspnoea, showed 

 that upon withdrawing a large supply of blood 

 from an animal, dyspnoea at once ensues, in 

 the form of inspirations, such as show them- 

 selves in all cases of dyspnoea induced by in- 

 sufficient conduction of oxygen to the re- 

 spiratory center. He called these heightened 

 inspirations, which proceed side by side with 

 an increased sinking of the blood-pressure, 



" pneumatorectic " respirations. This respira- 

 tion is distinguished from normal respiration 

 by regular deep inspirations of unchanged fre- 

 quency, in which the middle attitude of the 

 thorax removes further from the expiratory 

 than is the case in normal respiration. The 

 curve of respiration then passes over into the 

 normal, or convulsions set in, with increasing 

 blood-pressure, and altogether irregular re- 

 spiratory curves. After repeated heavy dis- 

 charges of blood, the pneumatorectic passes 

 into the "syncoptic" respiration, which is 

 characterized by deep inspirations of very in- 

 frequent occurrence, during which the attitude 

 of the thorax after expiration approaches even 

 nearer to that which it holds in a dead body. 

 Both the pneumatorectic and the syncoptic 

 respirations are perfectly regular and' typical. 

 The former shows itself immediately after a 

 heavy discharge of blood, the latter before 

 death. Between these extreme forms there 

 passed a series of others in an intercurrent 

 manner. Among them was a very frequent 

 superficial respiration, which was inadequate 

 to the necessities of life, and was called "hy- 

 pokinetic." Another form of respiration fol- 

 lowing heavy bleeding is that which shows 

 itself in periodical increasings of the ampli- 

 tudes in respiratory movements. 



Prof. Zuntz describes his experiments, with 

 Dr. Geppert, to determine whether the gases 

 of the blood, which are assumed to be the sole 

 stimulations of respiration, are adequate to ex- 

 plain the dyspnoea that follows increased mus- 

 cular activity. Quantities of blood were with- 

 drawn from a dog while at rest and while at 

 work without his perceiving what was done. 

 The comparative examination showed that the 

 increased respiration during work could not 

 be caused by the blood-gases alone, for the 

 contents of the arterial blood in carbonic acid 

 were less, and in oxygen considerably more, 

 than during a state of work. Another stimu- 

 lus must accordingly act upon the central or- 

 gans of respiration during work. It was shown 

 that the effect could not proceed from stimulus 

 of the respiratory muscles, or from reflex stim- 

 ulus provoked by the corporeal muscles. Prom 

 these facts, Prof. Zuntz conceived that he had 

 conclusively established that a substance, still 

 unknown, forming itself during the muscular 

 activity, proceeded with the blood to the re- 

 spiratory center and excited it. 



Prof. Albrecht, of Brussels, remarks that 

 the swimming-bladder of fishes is either found 

 in open connection with the intestinal tube, 

 or the connection between the two is obliter- 

 ated ; and in the latter case it might be as- 

 sumed that the communication in question had 

 existed in earlier stages of development. Many 

 naturalists are of opinion that the swimming- 

 bladder is homologous with the lungs, which 

 likewise represent a tube in communication 

 with the intestinal tube. This view is contro- 

 verted by the author, because in all fish the 

 swimming-bladder is placed on the dorsal side, 



