274 Notices respecting New Boohs. 



and completely destroy its oxygenous portion ; which could 

 not possibly happen if they possessed the power of emitting 

 oxygen gas. 1'he experiments, indeed, of Dr. Ingenhousz 

 himself teach us, that this supposed emission of oxygen gas 

 does not depend so much on the power of the leaves as ou 

 the quality of the water in which thcv are immersed ; for, 

 -if the water be previously boiled, little or no oxygen gas is 

 collected. Hence, then, we see, that to effect the separa- 

 tion of air from water the organized structure of the leaf is 

 not only not necessary, but that the quality of the separated 

 air is altogether different from what this supposed function 

 of the leaves ought to supply. No proof, therefore, of the 

 absorption and emission of gases, much less of oxygen gas, 

 by the natural functions of leaves, can be derived from these 

 experiments on plants immersed in water; and were the ex- 

 periments even more precise, they would not in the least 

 apply to the case of vcgcta!)les which flourish in tlie open 

 air." * 



The third and fourth chapters embrace the subject of 

 respiration. Scarcely an author from Ray to the present 

 period, who has either directly or indirectly treated of this 

 subject, whose opinions or observations arc not here cited. 

 The author's analysis bf the numerous opinions and vague 

 conjectures presents such an admirable specimen of deduc- 

 tive reasoning, as must ever "be eminently useful to science- 

 and true philosophy." The addition or subtraction of a syl- 

 lable in a verse would not be more sensibly felt than the 

 omission of a section in this inquiry, which consists of IQS. 

 Mr. Ellis concludes that nitrogen gas is brought in contact 



O to O 



With the respiratory organs of fishes and insects without un- 

 dergoing any change ; that oxygen is nut absorbed l)y these 

 organs, but, united to the carbon of the animal, ibrms car- 

 bonic acid ] and that it is not to the presence of the (gene- 

 rally supposed deleterious) carbonic acid, but to the small 

 proportion or totnl absence of oxvgen gas, that the cessation 

 of the animal functions is immediately to be ascribed." 



An examination of the " Sources of Carbon in Vegetables 

 and Animals, by which the Chatiges -a the Air are effected," 



constitute^ 



