296 Dr. Edwards, De V Influence 



A list of plants, &c. which exemplify all that is elegant in 

 form, beautiful in outline, and. graGeful in position, should 

 have accompanied the above imp^rfedt"* remarks,* but this must 

 be deferred to another opportunity, * ' ' ''^'^'^ 



n').t bitfi .tn^mffgWcroiT ?M£"9b om \o z^'^n^.i^muo1h ^^^hn^ ^ 



Z)^ r Influence deS Ag&ns Physiqmk^'Hi'F.TdlH^^ ^f4i^W. F. 

 . ;; uu;j j«y:i^4 -HiEdwards, D.M.,'&E ^^*^'^^**'^4 ^^"Jfi^iJ^ " 

 MVijji oi gme^jri «' ii'joni^jgmjjoiio ori r 



* [Continued from the last NumberO nj g-^yaoj. 



In our last number we presented our readers witK^'S'^i^^eral 

 abstract of the first part of this valuable work. The second 

 part refers to animals of the cold blood order, including Ji^A 

 and reptiles. The larvcB of the latter underw*ent some com- 

 parative experiments detailed in the first chapter, because 

 they partake of the nature both of fish and reptiles^ as to 

 their respiratory function ; the imperfection of their inter- 

 mediate state and developement of organization not inter- 

 fering with the objects in view, and the double mode of 

 aerification being exercised unequally. The skin of these 

 young animals furnishes them with the means of producing 

 the requisite changes in the blood hy absorption, ?L?,m i\\Q 

 adult, while it lives in water ; and the cutaneous respiration 

 goes on through this medium at a temperature which the 

 subsequent more perfect animal is unable to endure. The 

 object entertained is the influence of physical agents upon 

 the changes which these animals pass through in theii; form 

 and structure. 



An important condition of their advancement to maturity 

 seems to be, that the nutriment suspended in the water 

 should be in very small and limited proportions. Tempera- 

 ture also influences their constitutional changes. 



Sometimes the larvce pass through the winter iH their 

 primitive state ; a fact not generally known. Some tadpoles 

 were confined within wooden boxes submersed in the river 

 Seine, in which holes were perforated to allow the stream to 

 pass through, without the possibility of the animals' rising to 

 the surface of the water, and thus to inhale air. Others 

 were placed in a large vessel of Seine water renewed at 

 intervals, with power to rise above the surface. Ten in 

 twelve of the first box underwent no transformation, the 

 Others having gone partially through their change. But 



