KESPIRATION, AND ANIMALIZATiON. 



149 



on the varied proportion of alkaline and acid matter mixed with the juices 

 of the coloured parts of plants ; that green and yellow, for example, are 

 always produced by an excess of alkali in the colourable juices of the 

 leaf or flower ; and all the shades of red, by a predominance of acid ; while 

 a neutral mixture produces a white. And hence there is most green in the 

 summer season, when the oxygene is parted with most freely, as drawn 

 away by the rays of light ; while in autumn, when there is less separation, 

 the other colours of yellow and red are most frequent. 



Mr. EHis has also quoted a variety of experiments on dilferent kinds of 

 fishes, muscles, marine testacea, snails, leeches, zoophytes, and tadpoles, 

 in which it was found that the water wherein these animals had been 

 placed had lost a part of its oxygene, and received an addition of carbonic 

 acid, while its nitrogene had remained unaffected.* 



This hypothesis, however, requires confirmation, and is at present open 

 to many objectione. If caloric can permeate animal membranes, as Mr. 

 Ellis admits it to do, and unite by chemical affinity with the blood in the 

 blood-vessels, so also may oxygene in certain cases of combination. Mr. 

 Porrett has shown that the Voltaic fluid, when operatmg upon water, is 

 capable of carrying even water itself through a piece of bladder, and of 

 raising it into a heap against the force of gravitation ; and hence other 

 afl[inities may not only introcKice the oxygene of the respired air, or a part 

 of it, into the blood of the blood-vessels in the lungs, through the tissue of 

 the air-cells, but at the same time carry off' the superabundant carbone in 

 the form of carbonic acid, instead of its being thrown out in that of car- 

 bonic vapour. Nor have we any proof that carbone will dissolve in water, 

 and produce such vapour ; and hence such an idea is gratuitous.! 



Of the general operation, however, there is no doubt, whatever be the 

 manner in which it is performed : and by such operation the new blood 

 becomes assimilated to the nature of the system it has to nourish ; and the 

 old or exhausted blood both relieved from a material that may be said to 

 suffocate it, and reinspirited for fresh action. In this state of perfection, 

 produced from the matter of food mtroduced into the stomach, and elabo- 

 rated by the gases of the atmosphere, received chiefly by the act of respi- 

 ration, but perhaps partly also by the absorbing pores of the skin, the blood 

 on its analysis is found to consist of the following nine parts, independently 

 of its aerial materials : — first, a pecuhar aroma, or odour, of which every 

 one must be sensible who has been present at a slaughter-house on cutting 

 up the fresh bodies of oxen 3 secondly, fibrine,or fibrous matter ; thirdly, 

 uncoagulable matter, but no gelatine, which is a subsequent secretion ; 

 fourthly, albumen ; fifthly, red colouring matter ; sixthly, iron ; seventhly, 

 sulphur ; eighthly, soda ; and lastly, water. The proportion of these 

 parts vary almost infinitely, according to the age, temperament, and man- 

 ner of living ; each of these having a character that essentially belongs to 

 it, with particular shades that are often difficult to be laid hold of. 

 ^ Of these component parts, the most extraordinary are the red colouring 

 .matter, the iron, and the sulphur ; no'r are we by any means acquainted 

 with the mode by which they obtain -an existence in the blood. 1 have 

 already had occasion to observe, that albumen and fibrine are substances 

 formed by the action of the hving principle out of the common materials 

 of the food, and that it is probable the lime found in the bones and other 



* Inquiry into the Changes induced on Atmospheric Air by the Germination of Seeds, &c 

 Svo. 1807. As also, Further Inquiries into the Changes, &c. 8vo. 1811. 

 t Stud, of Med. edit. ii. vol, i. p. 474. Thomson's Annals of Philos. No. xliii. pp. 75, 76 



