BLOOD. 141 



same radical, consisting of carbon and hydrogen, is combined 

 with different atoms of water, or of Avater and oxygen ; I need 

 only refer to woody fibre,' starch, gum, sugar, and lactic acid. 

 We have sufficient grounds for assuming the existence of simi- 

 lar radicals in the chemical compounds of the animal body; and 

 if we knew more of the composition of the extractive matters, 

 we should doubtless find a radical common to all of them. In 

 many of these decompositions, which are extremely varying in 

 their nature, oxygen is undoubtedly absorbed, and carbonic 

 acid evolved, as indeed we see in the process of respiration. 

 Oxygen combines not merely with carbon ; it may also enter 

 into combination with hydrogen and form water, or with a bi- 

 nary or ternary radical, which it would oxidize. Hydrogen 

 and oxygen may, further, be either separated from or taken up 

 by these compounds, in the proportions in which they form 

 water. Thus quaternary compounds may be split into several 

 quaternaries with the same or a different radical, or into quater- 

 nary and ternary compounds, &c. These must, however, be re- 

 garded as mere possibilities, which, unless kept in check by 

 experiment, are capable of indeterminate extension. 



One of the most important conditions for the reciprocal ac- 

 tion between the cells of organs and the nutrient fluid is a 

 proper degree of warmth ; the requisite temperature varies in 

 difl'erent classes of animals, but its range is limited within 

 very narrow bounds, above or below which the action is im- 

 peded, or even destroyed, and death then ensues. If, there- 

 fore, we should regard the conditions of temperature as inde- 

 pendent of the organism, and unconnected with the phenomena 

 of life, these phenomena would be unavoidably and perpe- 

 tually disturbed, and the due course of the organism altogether 

 destroyed. 



The conditions for the production of a due temperature are 

 therefore based on the vital phenomena themselves, and in ac- 

 cordance with the principles of adaptation that are observed 



• [Woody fibre (lignine) . C,^ H^ Og ={C^2Uf,)0g 



^Starch .... C,, H,oO,o =(C,, H,) 0^ + 2II0 



Gum C,jH„0„ =(C.2H,)08H-3HO 



Cane sugar . . . C„ H,o 0,o + H0 = (C,2 HJ O^ -f-3H0 



Grape or diabetic sugar . C,, H,, 0,, + 3HO = (C,2 HJ O, + 6H0 



2 eq. Lactic acid . . C,o H„ 0,„ + 2H0 = (C,, H^) 0^ + 4H0.] 



