42 MEMOIRS OF 



of whose blood can return to the parts till after it has been 

 respired. Mammalia and birds not only live always in the 

 air, and move in it with more force than other animals with 

 red blood, but each of these classes enjoys the faculty of 

 moving, precisely according to the quantity of its respira- 

 tion. Birds, for instance, are as much impregnated with 

 air within as without ; not only the cellular parts of their 

 lungs are very considerable, but these organs have bags, or 

 appendices, which are prolonged throughout the body. 

 Thus, in a given time, they consume a much greater 

 quantity of air in proportion to their size than quadrupeds; 

 and doubtless it is this which gives to their fibres a prodi- 

 gious and instantaneous force, and which renders their flesh 

 fit to act powerfully on those violent movements which sus- 

 tain them in the air, by the simple vibrations of their wings." 

 In the concluding part of this first lecture, treating of the 

 Division of Animals, M. Cuvier sums up the great characters 

 of the animal kingdom, proceeding from Mammalia to Zoo- 

 phytes, or, in other terms, the whole range of animal life, from 

 man, to the simple pulpwhichscarcely merits the name of an 

 organized being. From this I do not find it possible to cite 

 any isolated passage, the whole is so beautifully linked to- 

 gether ; but the perusal of this portion alone is calculated 

 to enlarge our ideas respecting creation, to give us new 

 thoughts concerning the common occurrences of life, and to 

 lead us to a train of reflections, which mount upwards to 

 the great Source of that life which is presented to us in so 

 many extraordinary and elaborate forms. The rest of the 

 work consists of a description of these forms, external and 

 internal ; the minutest details concerning the use of each or- 

 gan are also given to us ; the chemical composition of each 

 part is explained ; the greater or lesser developement of this 

 wonderful machinery and combination is set forth ; the total 

 absence of some parts; the results of these differences, and 

 the action of the whole in the vast field of nature, all are 

 laid before us with a clearness and precision that are truly 

 admirable. For, although endowed with imagination, 

 brilliancy of ideas, and eloquence of language, M. Cuvier 

 has in this, as well as his other scientific labours, affirmed 

 only, " that which he has seen and touched,'' and, far from 

 wishing to persuade by other means than positive evidence, 



