306 



RESPIRATION. 



with hydrogen gas * and the addition of a 

 saline solution, of the same strength as that 

 existing in the blood f , will not impart to it 

 the arterial hue, if oxygen gas be not at the 

 same time present. The oxygen gas, there- 

 fore, acts directly, and not ^indirectly by re- 

 moving the carbonic acid, in changing the 

 colour of the blood; but as a small quantity 

 only of this gas is sufficient, when the salts 

 are present in their usual quantity, to produce 

 this effect J, the action of the oxygen, in 

 changing the colour of the blood in respira- 

 tion, will be aided by the presence of the 

 salts. 



In the present state of our knowledge, 

 there is some difficulty in deciding whether 

 the reddening of the blood by the absorbed 

 oxygen be entirely a physical action, or 

 whether it be partly physical and partly che- 

 mical, seeing that several accurate observers, 

 who have recently investigated this point, 

 have arrived at very different conclusions. 



The opinion, first promulgated by Dr. 

 Wells , that the change from the venous to 

 the arterial hue arises from an increased re- 

 flection of light in the red particles, caused 

 by the presence of the absorbed oxygen, and 

 without any chemical change upon the haema- 

 tosine, has of late obtained several supporters. 

 Those who have adopted this view do not, 

 however, agree in their explanation of the 

 manner in which this increased reflection of 

 light is effected ; some maintaining that it 

 arises from an alteration in the form of the 

 red corpuscles, and that this change consists 

 in the biconvex corpuscles of the venous 

 blood, becoming biconcave in the arterial 

 blood || ; while others believe that the action 

 of the oxygen on the blood is analogous to 

 that of the nitrous oxide on the solutions of 



* Bischoff, Dr. Maitlancl, Nasse, and Marchand. 



t Gregory and Irving (vide London Medical Ga- 

 zette, vol. xiii. p. 814. 1834). Nasse (Wagner's 

 Handworterbuch,&c., Band i. S. 182) affirms that even 

 concentrated solutions of muriate of soda, nitrate of 

 potassa, and carbonate of potass, cannot impart the 

 true arterial hue to venous blood, without the pre- 

 sence of a small quantity of oxygen ; and that 

 when Stevens saw the blood redden under the air- 

 pump, there must have been sufficient oxygen still 

 present in the rarefied air to act on it with the aid of 

 the salts. 



J Nasse (opus cit. p. 182). He also infers from 

 his experiments that oxygen can redden the blood 

 without the presence of salts (p. 187). 



London Philos. Transact, for 1797, p. 41G. 



|| Scherer, Ecuter, and Gulliver. Mulder (The 

 Chemistry of Animal and Vegetable Physiology, 

 p. 341, 342.) also contends that the arterial hue 

 depends upon the red particles assuming the bicon- 

 cave form and reflecting more light, but he gives a 

 very different explanation of the cause of the change 

 in the form of the red particles from the other support- 

 ers of this view. According to Mulder, part of the 

 oxygen absorbed unites with some of the proteine 

 compounds in the blood in the lungs, and forms oxy- 

 proteine, and this furnishes a thin envelope to the 

 red corpuscles, and by its contraction causes them to 

 assume the biconcave form. This opinion is sup- 

 ported neither by direct observation nor by experi- 

 ment. Marchand (Journal fur praktische Chemie, 

 Band xxxviii. 270, 277) and Dumas (Comptes 

 Reudus for 1840, torn. xxii. p. 900) after separa- 



the salts of iron, changing their colour with- 

 out entering into chemical union with them.* 

 We may, in the meantime, conclude that 

 the change in the blood from the venous to 

 the arterial hue in the lungs, is a physical and 

 not a chemical action ; and that though there 

 is pretty strong evidence in favour of the 

 opinion that this physical change consists in 

 an alteration of the form of the red corpuscles, 

 yet it is not free from doubt. 



The various systematic works on Physiology are 

 not included in'the following Bibliography of Re- 

 spiration. 



BIBLIOGRAPHY. Mayow, Tractus Duo, quorum 

 prior agit de Respiratione: alter de Rachitide, 

 Oxon. 1009. Lower, Tractus de Corde, &c, Caput 

 iii. De Colore Sanguinis, Lugduni, 1722. Priestley, 

 Observations on Respiration and the Uses of the 

 Blood, iii Philos. Transact, of London for 1770. 

 Lavoisier, Experiences sur la Respiration des Aui- 

 maux, et sur les Changemens qui arrivent a 1'Air en 

 passant par leur Poumons, in Memoires de 1' Aca- 

 demic Royale des Sciences de Paris, for 1777, pub- 

 lished in 1780. Lavoisier and La Place, Me'moire 

 sur la Chaleur. Article IV. De la Combustion et de 

 la Respiration, in Mem. de 1'Acad. Roy. des Sciences 

 for 1780, published in 1784. Crawford, Experi- 

 ments and Observations on Animal Heat, &c., Lon- 

 don, 1788. Goodwyn, On the Connexion of Life 

 with Respiration, &c., London, 1788. Lavoisier and 

 Sequin, Premier Me'moire sur la Respiration des 

 Aiiimaux, in Mem. de FAcad. Roy. des Sciences for 

 1789; and Sur la Transpiration des Animaux, in 

 Mem. de FAcad. Roy. des Sciences for 1790. Men- 

 zies, Tent. Inaug. de Respiratione, Edinburgh, 1790. 

 Hassenfratz, Me'moire sur la Combinaison de 1'Oxi- 

 gene avec le Carbone et PHydrogene du Sang, sur la 

 Dissolution de 1'Oxigene dans le Sang, et sur la 

 Maniere dont le Calorique se de'gage, in Annales de 

 Chimie, torn. ix. 1791. Coleman, On natural and 

 suspended Respiration, London, 1791. Vauquelin, 

 Observations Chimiques et Physiologiques sur la 

 Respiration des Insects et des Vers, in Annales de 

 Chimie, torn. xii. 1792. Wells, Observations and 

 Experiments on the Colour of the Blood, in Philos. 

 Transact, of London for 1797. Sir Humphry Davy, 

 Researches Chemical and Philosophical, &c., Lon- 

 don, 1800. SpaUanzani, Me'nioires sur la Respira- 

 tion, traduits par Senebier, Geneve, 1803. Bostock, 

 On Respiration, Liverpool, 1804. Henderson, Expe- 

 riments and Observations on the Changes which the 

 Air of the Atmosphere undergoes by Respiration, 

 particularly with regard to the Absorption of Nitro- 

 gen, in Nicholson's Journal of Natural Philosophy, 

 vol. viii. 1804. Brande, A concise View of the 

 Theory of Respiration, in Nicholson's Journal, vol. 

 xi. 1805. Pfaff, New Experiments on the Respi- 

 ration of Atmospheric Air, &c., in Nicholson's Jour- 

 nal, vol. xii. 1805. Ellis, On the Changes of At- 

 mospheric Air in Respiration and Vegetation, parts 

 i. and ii. Edinburgh, 18071811. Allen and Pepys, 

 On the Changes produced in Atmospheric Air 

 and Oxygen by Respiration, in Philos. Transact, of 

 London for 1808 : and, On Respiration, in Philos. 

 Trans, for 1809. Berthottet, Sur les Changemens que 



ting the red corpuscles from the other constituents of 

 the blood, and washing them in a solution of sul- 

 phate of soda, found that they still changed from the 

 venous to the arterial colour on the addition of oxy- 

 gen. Dumas concludes, that neither the presence of 

 albumen nor fibrin is necessary to enable oxygen to 

 redden venous blood; and Marchand, after a careful 

 experimental investigation, affirms that the supposi- 

 tion that the changes of colour in the blood are from 

 a chemical action, is attended with insuperable diffi- 

 culties (opus cit. Band xxxviii. S. 278). 

 * Magnus and Marchand. 



