THE COASTS OF SICILY. 263 



same time evident that these different acts, being all 

 accomplished at the same point, cannot be executed 

 with the same degree of perfection as if each of them 

 resulted from the action of a special instrument. 

 We can, therefore, fully comprehend the full value 

 of the principle which was developed more than 

 twenty years ago by M. Milne Edwards, and which 

 may be summed up in the following terms: the suc- 

 cessive degrees of perfection attained by the different 

 organisms in the animal kingdom depend upon the 

 extent to which functional labour * is divided. 



An attentive study of the circulation, when con- 

 sidered in all its bearings, is well adapted to demon- 

 strate the very suggestive nature of this principle ; 

 while at the same time it shows how it leads to the 

 coordination of facts, which at first sight appear to 

 be incongruous or even in direct antagonism. This 

 function is effected in the higher animals by the aid 

 of a very complicated apparatus, the principal parts 

 of which have received the names of heart, arteries, 

 veins, lymphatics, and lacteals. The heart sends the 

 blood through the arteries towards every part of the 

 body, from which this fluid is returned to it through 

 the veins. The lymphatics convey to the same cir- 

 culatory centre the lymph, which is a transparent 

 liquid, exuding, if we may use the expression, from 

 all the organs. The lacteals transport to the same 

 centre the chyle, which is the immediate product of 

 digestive absorption. These different liquids, which 

 are enclosed in veritable tubes, follow with admirable 



* I have already referred to these views in Chapter II., on the 

 Archipelago of Brehat. 



8 4 



