6G2 



PHYSIOLOGY. 



supply of oxygen notwithstanding the great loss 

 of haemoglobin. The transfusion with saline 

 solutions after bleeding does not appear to have 

 any special effect upon the respiratory exchange ; 

 it without doubt enables the animal to bear a 

 greater loss of blood than it could otherwise, 

 but it appears to owe its beneficial effects chiefly 

 to the mechanical assistance which it gives to 

 the circulation by filling th'e blood vessels. The 

 solution also probably economizes the fluids in 

 the tissues, and removes the thirst, which is 

 often a marked symptom of a great loss of 

 blood. Any distinct effect upon the respiratory 

 change is not shown by the experiments. The 

 results also afford another proof that the vital 

 combustion proceeds chiefly in the tissues of 

 the body and not in the blood. A review by the 

 authors' of the previous work of other observers 

 shows that their results, with the exception of 

 those of Bauer, agree on the main points with 

 those obtained in the present investigation. It 

 also shows how much experimental evidence has 

 accumulated to support the position taken up 

 and defended by Pfliiger upon the question of 

 the relationship of the tissues to exchange of 

 material. 



Experiments by Signora Traube-Mengarini 

 have established the presumption that fishes can 

 recover from death by asphyxia if opportunity 

 be afforded to the blood of freeing itself from 

 COa by combination with substances introduced 

 into the surrounding medium. In experiments 

 made by Dr. Jordi at Bern on the causes of 

 asphyxia, fishes which had become helpless in 

 the condition immediately preceding death by 

 exhaustion of air recovered when transferred to 

 another vessel containing boiled out water, and 

 survived for periods of from ten to seventeen 

 hours Fresh fishes introduced into the water 

 which had been tenanted by the dead fish could 

 live in it for several hours, and, when a little 

 sodium hydrate was added to the water, for a 

 whole day. The addition of sodium hydrate to 

 the water caused a fish dying of asphyxia to 

 revive, and prolonged its life for more than forty- 

 five hours. The addition of carbonic acid was, 

 however, destructive in proportion to the amount 

 of the substance introduced. From experiments 

 made upon himself to determine how much C0 a 

 he could support in inspired air, Dr. Jordi found 

 that carbonic dioxide in certain proportions 

 stimulates respiration. 



It has been generally assumed on the evidence 

 of a small number of not wholly satisfactory ob- 

 s.Tvations that the metabolism of cold-blooded 

 animals, contrary to what is the case with warm- 

 blooded animals, varies uniformly with the tem- 

 perature. Further observations have been made 

 upon the subject to sec if this were actually so 

 by H. M. Vernon, who measured the carbonic 

 acid evolved by frogs at temperatures from to 

 30 C. The chief conclusions arrived at in Mr. 

 Vcrnon's paper are that the carbonic acid given 

 off by intact frogs on gradual wanning varies 

 within narrow limits from T C. up to about 17'5 

 C., but above this point it increases rapidly with 

 the temperature. On cooling, it as a rule be- 

 comes nearly constant from about 1?'5 to 12'5 

 or 10, and then decreases uniformly with the 

 temperature. In curarized frogs and frogs with 

 their bulb injured the carbonic-acid discharge 



increases uniformly with the temperature. If 

 frogs be warmed and cooled rapidly several times, 

 the curves of carbonic-acid evolution subsequent- 

 ly obtained are either perfectly uniform or show 

 abnormally marked changes at varying tempera- 

 tures. The curves do not become normal again 

 for several days after. The respiratory quotient 

 of winter frogs in which the bulb has not bini 

 injured is about '63, that of frogs with the bulb 

 injured about '45, and that of curarized frogs 

 and frogs subject to rapid temperature changes 

 about '5. 



Circulation. In connection with Eykman's 

 researches on the question whether sojourn in 

 tropical regions causes an alteration in the blood 

 of Europeans, Dr. Grijus, of Batavia, Java, has 

 developed a new method of determining the vol- 

 ume in question, and has also determined the 

 influence upon the blood of different substances 

 in watery solution. Defibrinated blood was sub- 

 jected to a whirling motion in small calibrated 

 tubes; the height of the layer of cruor was meas- 

 ured, the serum removed,' and the cruor mixed 

 with the solution in question and again whirled. 

 The solution in which the height of the cruor was 

 the same as in the serum was isotonic. The con- 

 centrations of the solutions of salt, cane sugar, 

 miik sugar, oxalate of sodium, potassium chlo- 

 ride, and asparagin, that leave unaltered the cruor, 

 were really found to be in isotonic relation. Oth- 

 er substances urea, ammonium chloride, ammo- 

 nium nitrate, glycerin, and alcohol are in no 

 concentration isotonic with the blood corpuscles. 

 Potassium bichromate and corrosive sublimate 

 affect the blood corpuscles considerably in each 

 concentration. On these preliminary results the 

 author has founded a new method for the deter- 

 mination of the volume of the blood corpuscles. 



A new method of measuring the amount of the 

 circulating blood and the work done by the heart, 

 described by Prof. Zuntz, depends on the fact 

 that as long as the peripheral resistance is con- 

 stant, blood pressure is dependent on the volume 

 of blood driven into the aorta by the left ventri- 

 cle. When the heart is inhibited by stimulation 

 of the vagus the blood pressure falls, and if now 

 a volume of blood is injected into the aorta suf- 

 ficient to raise the pressure again to the normal, 

 then this volume must be equal to that which the 

 heart ordinarily drives into the arterial system. 

 The method has shown itself to be reliable in 

 experiments made on dogs, and has already yield- 

 ed some interesting results relating to the circu- 

 lation which are to be further investigated. 



Additional results of his experiments on the 

 influence of rarefied and compressed air on the 

 circulation have been communicated by Dr. Ad. 

 Loewy, of Berlin. As was shown in earlier ex- 

 perim'ents, a diminution of pressure to about 450 

 millimetres of mercury was tolerated very well 

 and did not lead to any real disturbance, and the 

 lowered oxygen tension, produced either by still 

 greater rarefaction or by the addition of carbonic 

 acid to the air breathed, is compensated for by 

 deeper respiration. The author desired now to 

 determine by experiment whether, with rarefac- 

 tion of the air, compensating changes can be ob- 

 served in the vascular system. In particular he 

 determined the velocity of the blood flow by the 

 method recently devised by Prof. Zuntz (sec 

 above) in animals which respired in rarefied air 



