NATURAL GENERA. 299 



taken for granted. Let us now take the lion, the tiger, and 

 the leopard, and examine them in the same manner. We 

 arrive at the same conclusion. They have a general resem- 

 blance to each other, but differ " inter se" in particulars. 

 Now the resemblance they bear to each other constitutes the 

 genus, the difference between them the species. 



A comparison of these two groups, one with the other, will 

 show that hardly a single character is there in common 

 between them. The individuals of the first feed upon grass 

 and herbs ; those of the second upon the flesh of other ani- 

 mals : according to their different habits their organs are 

 formed ; and surely no two groups can be more dissimilar. 

 All that they resemble each other in is, that the individuals 

 of both are viviparous, and suckle their young, characters 

 hitherto thought no more than sufficient to class them 

 equally as " mammalia." This difference of groups exists as 

 strongly in insects ; and it is a difference, I think, as clearly 

 pointed out by nature as the difference of one species from 

 another. 



The principal argument of the unbelievers in genera is, 

 " that although it may be extremely easy to form two groups 

 apparently unlike each other in every respect, yet a series of 

 insects may be formed which shall so gradually connect any 

 two such groups, that it shall be impossible to say where the 

 one terminates and the other begins ;" hence they deduce that 

 genera do not exist. 



Now if this reasoning is good for any thing, it ought to be 

 of universal application ; but will it lead us to doubt that 

 animals and vegetables are separated from each other by 

 nature, because the line of separation is not clearly discernible? 

 for so great is the difficulty naturalists have experienced in 

 drawing this line, that the only characters of distinction 

 hitherto given, are not wholly free from objection. Will it 

 lead us to conclude that matter is either all organic, or all 

 inorganic, because " the line of demai'cation between the 

 mineral kingdom and organized matter is allowed to be 

 indistinct ? " 



But if the gradual merging of one genus, so called, into 

 another, be sufficient to show that genera exist not in nature, 

 it will follow that neither do " orders " exist ; for it cannot be 

 doubted that insects exist which will link every order together. 



