INTRODUCTION. 



hundred thousand species of Plants and Animals existing on our 

 globe, it is evident that this labour must be greatly subdivided, 

 that it may be undertaken with any chance of success. Each 

 Naturalist chooses a department most conformable to his own 

 taste, or to his opportunities for pursuing it ; one confining him- 

 self, for example, to the study of the external forms of some 

 particular group; another to the examination of its internal 

 structure ; a third devotes himself to physiological inquiries ; and 

 a fourth to the observation of the habits and instincts of the 

 respective beings, in a state of nature. Now it would be quite 

 possible to pursue any of these inquiries without a knowledge of 

 the names, which had been imposed upon the objects that fall 

 under our observation ; and the pleasure derived from such pur- 

 suits is but little impaired by this ignorance. What does it 

 matter, for example, to the Microscopic observer, whether he is 

 or is not acquainted with the name given to some Animalcule, 

 whose movements he might be watching with the greatest inte- 

 rest, by some former observer, who very probably knew much 

 less of its structure and actions than himself ? But if we wish 

 to unite or compare our observations with those of others, a 

 knowledge of names becomes highly desirable, in order to save 

 the time, trouble, and uncertainty which will otherwise be in- 

 volved. The Author may mention a recent example of this 

 kind, from his own experience. He recently observed a very 

 active movement of the reproductive granules (VEGET. PHYSIOL. 

 424) in a species of Sea-weed, in which, to the best of his 

 belief, it had not been previously seen. Now, in order to place 

 this observation upon record, it might certainly answer to give 

 such a general description of the plant as would probably serve 

 to point it out to other observers ; but such a description, not 

 drawn up by a Botanist who had paid especial attention to the 

 study of the Algas, would be very probably erroneous or defective, 

 and might consequently leave it uncertain which species of Sea- 

 weed was really meant. But by ascertaining the name of this 



