1867.] ( 153 ) 



II. NEKYE STKUOTUEE AND FOKCE. 

 By Holmes Coote, F.E.C.S., 



Of St. Bartholomew's Hospital. 



A superficial examination of the earth's crust shows, that frora 

 the most remote epochs there has been a succession of animal forms 

 corresponding with the nature of the atmosphere in which such 

 animals were trained to live ; also that the transition from sea to 

 estuary, and from estuary to river and thence to dry land, has been 

 slow and without violence ; and that among the marine strata there 

 are mingled both animal and vegetable productions belonging to 

 fresh-water life or the inhabitants of dry land. The study of 

 geology therefore embraces not only the structure of the earth, but 

 likewise natural history, comparative anatomy, and the physical 

 sciences generally, and hence proves to its followers a source of 

 endless intellectual enjoyment. 



Among the early ideas, which strike us, is the important part 

 played by the invertebrate or lower forms of animals, as compared 

 with the vertebrate, in the history of the revolutions of the globe : 

 through their ceaseless operations, islands are raised in the middle 

 of the ocean, while from their debris such masses as those which 

 constitute our chalk-cliffs are constructed. Whatever may have 

 been the decree of the divine will as to their first creation, they 

 must each in their generations have increased and multiplied until 

 their missions were respectively accomplished. Some inquiry into 

 their nature and organization becomes therefore interesting. 



There are two great functions in operation in all forms of animal 

 life, without which the race becomes extinct, namely, alimentation 

 and reproduction. Even in the most complex organisms, such as 

 man, endowed with the highest faculties and capable of the grandest 

 mental efforts, the desire to " eat to live " and the fostering love 

 of offspring constitute the most abiding emotions. In savage life 

 the hunter will endure any amount of fatigue to secure his supply 

 of food, and will fight to the death for the preservation of his 

 young ; and so among brute animals, though in a less degree, until, 

 in the more simply organized, the love of self consumes all other 

 feelings under the form of a reflex action of personal wants, and 

 the young are provided for by those mysterious laws whose pheno- 

 mena we may study, whose source and directing power we can 

 refer only to the " One great Cause." 



In the vertebrata, the organs of alimentation consist of a tube 

 with oral and anal aperture ; of teeth, to seize and grind ; and of 

 numerous accessory glands, such as parotid gland, liver, pancreas, 

 &c. By means of these the nutritive material is prepared, that it 

 may be subjected to other changes, which convert it into blood; 



