the Origin of Intestinal IForms^ 38t 



processes, and will only harm them, whenever it occurs, In cold-: 

 blooded vertebral animals, whose regenerative power is strong, 

 and whose wounds and fractures will of course heal easily, no 

 inflammation usually accompanies the regeneration ; and, in 

 the warm-blooded, it cannot be too carefully guarded against. 

 This great and fundamental rule in surgery and medical prac- 

 tice has been discussed in Britain, with all due attention, by Dr 

 James Macartney, in his treatise on Inflammation, the result of 

 many years' laborious inquiry. The phenomena just described 

 in reproduction and in formations generally, appears to be pre- 

 cisely similar in invertebral animals, and, with certain modi- 

 fications {vide Schleiden, 1. c), in vegetables too. In the Sal- 

 pas, whose texture is regarded by some naturalists, so very 

 simple, almost like a jelly, as by Professor Meyen at Berlin 

 (Acta Loop. Carol, vol. xvi. p. 373). I lately had an opportunity 

 of observing, not only that the serous membranes are formed 

 just as in vertebral animals, by a layer of primitive cells, 

 like a piece of beautiful mosaic work, but also, that, in the 

 fa'tus, these cells are formed gradually upon the nuclei. At 

 the same time, I had an excellent opportunity of observing, 

 not only that the muscles of the Salpas have the same struc- 

 ture, with transversal stripes, as those of the vertebrate and 

 articulate animals ; but also that this texture was gradually 

 developed in the foetus, precisely in the way stated by Professor 

 Valentin, cells arranging themselves in rows, in which the nu- 

 clei continue visible for a long time, the number of the rows 

 at first being less, and each row thicker than the primitive 

 fibres of the muscles into which they are metamorphosed. 



Upon the whole, there can be no doubt the phenomena are 

 essentially the same in all processes of nutrition and repro- 

 duction, and that equivocal generation, if it existed, w^ould pro- 

 ceed in exactly the same w^ay. As it must further be granted 

 to Professor Burdach, that it would be a vain presumption to 

 trace the limits of possibility in nature, it cannot be deemed 

 impossible that the primitive cells, once formed, might be 

 metamorphosed in any direction ; and that animals with mus- 

 cles and nerves might as well be formed in this way, as ani- 

 mals and plants whose whole body was composed of cells. 

 Nay, it may even be granted, that if spontaneous generation 



