466 THE POPULAR SCIEXCE MONTHLY. 



rolling up of the single phyllate cotyledon, these adhesions must be in- 

 numerable. Otherwise there would be no stems to plants of this class. 

 A careful analysis will always enable us to trace the original layers, 

 and, wherever reduced to a simple leaf, to find the law invariable. 



It is manifest that all these creatures live externally. The leaf is 

 the type of all ; and every metamorphosis is some modification of a 

 leaf. Even creatures of a single cell may be regarded as diminutive 

 leaves ; and all leaves are compounds of simple cells. The point is, the 

 true manner of organization or of life. The grand peculiarity of all of 

 them is that the great disturber — life-destroyer and life-giver, atmos- 

 pheric oxygen — must come in direct contact with each and every cell. 

 Organisms living in tliis way are called j^lants — a term w^hich has no sci- 

 entific meaning or value, since it indicates no relation to other creatures. 

 All other living creatures constitute but one other grand kingdom ; 

 animals, another unscientific term. Unscientific as the terms are, it is 

 generally supposed that we know pretty well to what they apply. We 

 understand these are the first two branches from the main root of or- 

 ganic life, springing from the same original germ, and expanding into 

 two great trees, never uniting nor mingling their boughs any more. It 

 is easy to see the correlation of these two ; the true distinction between 

 them. 



The so-called plant never loses the type or plan of the original leaf, 

 of the primitive cell. It always remains phyllate, and living, as it 

 were, cell by cell, in external relations to the air and the sources of nu- 

 trition. The so-called animal is more complicated. It differentiates 

 completely the points, or spots, or organs of aeration and of nutrition; 

 devotes one part of the organism to nutrition, and another to oxygena- 

 tion. This is not all. Thus far probably all cells agree. But in ani- 

 mals the organs and functions of nutrition, at least, are in some fold 

 of the tegument or sarcode, so that they store away their food in a 

 special receptacle, and carry it about. This is as perfectly true of the 

 most elementary amoeba as of the elephant. This view of the ground 

 of classification has been rejected by naturalists — by Dr. Carpenter 

 among others ; but this was done years ago, inconsiderately, and with- 

 out the aid of recent advances in biology. 



The amoeba, although a mere drop of jelly, in^yrovises a pocket, or 

 stomach, for the reception of its food, which, for the time being, is dif- 

 ferentiated to nutrition. The so-called plant, on the contrary, has its 

 mesentery, as well as its apparatus for aeration, external to the organ- 

 ism. The animal involutes a part of its investing tegument ; takes 

 the mesentery, at least, into the inside of the body ; and, in the higher 

 orders, the lungs also. 



The scientific relations of the two kingdoms are well indicated, 

 therefore, in the terminology which classifies the one as Exothens — 

 external livers ; and the other as JEndothens — internal livers. 



As to their life, and the elements of organization, they are precisely 



