246 DR. CARUS ON THE KINGDOMS OF NATURE, 



carbonic acid gas, with the additional one of nitrogen, which peculiarly 

 belongs to this kingdom, and the volatile nature of Avhich perfectly 

 agrees with the rapid merging of animal bodies in the universal life of 

 nature, as soon as their individual life is extinct ; to which passage, 

 however, the earthy parts, such as bones and shells, offer somewhat 

 longer resistance. In regard to the internal formation of the solid parts 

 of the animal body, it has been already remarked (see p. 244) that the 

 spherical type, in so far as it is peculiar to animal forms in general, is also 

 visible in the basis of all animal matter, so that the molecular substance 

 is the basis of the collective animal body. If Ave now reflect likewise 

 how in the Infusoria and Priestley's matter, the rudiments of the animal 

 kingdom appear as so many animated globuli, we shall thence perceive 

 that tlie largest animal bodies themselves must be viewed as an innu- 

 merable aggregate of Infusoria, but at the same time united into a living 

 whole. It is moreover worthy of remark, that very essential differences 

 present themselves in respect to the primary formation of the animal 

 body in its different systems. It is also a remarkable fact, that in the 

 organs exclusively proper to the animal, — for instance, in those of sense, 

 motion, and the nerves, — this molecular mass is clearly discernible, partly 

 as the marrow of the nerves (a peculiar grey substance), partly as de- 

 veloped nervous and muscular fibres ; while in the organs which are 

 more immediately borrowed from the plant (the vascular system, the 

 skin, and tlie intestines), we remark again a very decided tendency to 

 cellular formation. 



We have now before us two modes of perceiving in its true nature the 

 further formation of the primary animal mass into the single organs of the 

 animal body; either that of attentively watching the development of one 

 complete animal organism in its different stages, or that of observing 

 the succession of the species according to the order of animals in the 

 development of their animalism. Of these two we shall give only the 

 principal outlines of the first series of formation*, in which we shall find 

 a great analogy to tlie development of the plant, but more especially 

 a manifold confirmation of that which we have advanced in regard to 

 the metamorphosis, or rather elevation, of vegetable into animal life. 

 But in tracing the development of the individual animal body through 

 its several stages, we shall take as the main object of our observations the 

 human organization as the most perfect ; and thus we shall have occa- 

 sion to recur to that of other animals in those cases only in which the 

 observations made on the human being itself are deficient in regard to 

 its first rudiments. 



* The observation of the development of organization in the series of ani- 

 mals, is the idea upon which Carus's Manual of Zootomy is founded, to which 

 he here refers his readers. 



