4 IMPORTANT TO THE NATURALIST. 



have disappeared from among existing races, or whether they 

 still find their living representatives ; and refreshed with this 

 information he again ventures to chronicle, with a bolder 

 hand, the catastrophes and revolutions which the world has 

 suffered in its evolution from chaos to its present fixed and 

 ordered magnificence. The Conchologist is an indispensable 

 ally to the geologist, to satisfy whose demands he has entered 

 on inquiries of the nicest nature, requiring a delicacy of obser- 

 vation, and a tact in detecting differences amid resemblances, 

 which long and diligent exertion can only give ; and a know- 

 ledge of the habits of living shell-fish which has been the result 

 either of much patient observation, or the conclusions of a 

 strict logic. So that if Conchology can be followed as a 

 pleasant relaxation from other duties, your experience will 

 ere long satisfy you how wrongfully it has been considered 

 by many as such only : the obstacles to its mastery in all its 

 bearings are indeed sufficient to stimulate your perseverance 

 to overcome them, and more than sufficient to scare away from 

 the pursuit most of those who natter themselves they act a 

 courteous part when they complacently allow that you are at 

 least harmlessly engaged ! * 



For the present, however, you and I will study Conchology 

 with the view neither of forming a cabinet of shells, nor of 

 becoming auxiliaries to the geologist, but as an important 

 branch of natural history which cannot be neglected by any 

 one who is desirous to obtain a correct knowledge of the 

 animal economy, -f of the structure and habits of animals in 

 general, and of their mutual dependencies and relations. To 

 the naturalist who studies in this spirit, no one class, however 

 apparently insignificant, is perhaps less worthy his attention 



* Deshayes has applied his knowledge of Conchology to determine the 

 temperature of Europe during the tertiary periods ; and Biology may draw 

 from Conchology numerous materials. — Charlesworth's Mag. Nat. Hist. i. 

 9—16. 



T " Neither will it he requisite for me to enlarge upon the advantage of 

 extending your views to the examination of the animal kingdom in general, 

 with reference to the physiology of man : for it is obvious that our know- 

 ledge of the functions and structure of the human body would be very imper- 

 fect without a comparative investigation of those of animals. Indeed all the 

 important discoveries of modern times, with regard to the human economy, 

 have been derived from observations made on the lower animals. Among 

 the many examples of the truth of this proposition, we may cite the disco- 

 very of the circulation of the blood, by which the name of Harvey has been 

 immortalized ; that of the lacteals by Asellius ; and that of the thoracic 

 ducts by Pecquet ; all of which were obtained from this source. The works 

 of Haller bear ample testimony to the advantage which has resulted to phy- 

 siology from the cultivation of this wide field of inquiry." — Dr. Roget, Lect. 

 on Hum. and Com. Physiology, p. 97. 



