of invertebrate: animals. 399 



all that happiness and delight which his existence in this world is calculated to 

 confer. 



There are two ways of arranging the objects in these kingdoms in a systematic 

 manner. By one way, particular properties or qualities of objects are made the 

 basis of arranging them into a system. This method is artificial, and although 

 founded on natural properties, yet, taking only single properties into considera- 

 tion, objects are often brought together which are very dissimilar in their real 

 nature. Such systems are called artificial. The celebrated botanical system of 

 Linn^us is " a good illustration" of this mode of arranging natural objects, 

 exhibiting both its advantages and defects. The other mode of classifying natural 

 objects is by considering all the properties and qualities they may present, and 

 by giving a proper relative value to each, to bring those objects together which 

 most resemble each other in their real nature. These are called natural systems, 

 and are the only ones by which science can be advanced. 



In looking at the three kingdoms of Nature, we find that they do not pass into 

 each other by an ascending line, but that there is a central point from which 

 each appears to start, and the further any individual of one kingdom may be 

 removed from this point, the less does it resemble individuals in the other king- 

 doms. But close to this central point it is very difficult to determine to which 

 kingdom the objects belong. It is at this part of our plan that we must station 

 those minute and, to the naked eye, invisible particles which are constantly 

 moving about in water, and which may or may not be inanimate matter, or the 

 germs of vegetables or animals. It is here we must refer those inscrutable beings 

 called "first plants" and "first animals" {Protophyta and Protozoa), which have 

 caused so much perplexity to scientific observers, some thinking them all plants, 

 others considering them all animals, whilst some again believe they begin their 

 existence as plants, and finish as animals ; and others conceive they commence 

 life as animals, and finish as plants. 



Amongst those beings which seem to claim a situation amongst animals on 

 account of their movements is the Oscillatoria. There are, however, among the 

 tribe of plants called Confervce many others which exhibit, both in their embryo 

 and perfect state of existence, motions as singular as the Oscillatoria. Ulva 

 bullata is one of these ; and the peculiarly fantastic movements of its germs or 

 ovules are calculated to excite the greatest interest in this obscure part of the 

 dominions of Nature. 



In tracing up the line of succession in the Animal Kingdom, it is difficult to 

 know exactly at what point to begin, two or three of the lower groups of animals 

 claiming in some characters a close relation to the Vegetable Kingdom. 



However,without entering into the various claims of these groups to be considered 

 the lowest in the animal scale, I shall commence my observations on the Animal 



3o2 



