the Origin of Intestinal JVorms^ 335 



mud ? We give crocUt to the statements of Trembley, when 

 he tells us of his having cut the hydra into innumerable pieces, 

 every one of which became a hydra. Howsoever marvellous 

 these statements, they are not repugnant to the common laws 

 of reproduction, or of vital phenomena in general ; but let him 

 tell us that out of a single portion arose a worm, a plant, or any 

 thing but a hydra of the same species, and we assuredly reach 

 the realms of fable. But, such a metamorphosis it may be an- 

 swered, of the substance of one organism into another of a 

 wholly different kind, has been directly observed. M. Turpin, 

 it is stated, has seen (Ann. des Sc Nat. tome 8) the globules of 

 milk degenerating into a certain species of cryptogamous 

 plant, viz., the Pencillium glaucum, Linn., an observation ana- 

 logous to that of M. Dutrochet, when he beheld muscular fibres 

 formed in albumen by the influence of Galvanism, and also 

 to that of Mr Cross, when he saw infusoria produced in the 

 same way. Accurate observations, however, will at once de- 

 monstrate the error and the fallacy of all such observations. 



CHAP. IV. THE GREAT FERTILITY OF INTESTINAL WORMS IN- 

 COMPATIBLE WITH THE HYPOTHESIS OF THEIR SPONTANEOUS 

 GENERATION. 



Sect. 1. The chief Characteristic of the structure of Intestinal 

 Worms is the immense development of the Heproductive St/stem, 

 — The highly complicated structure, both of the infusory ani- 

 malcules and intestinal worms, constitutes, as we have stated, 

 a strong argument against their spontaneous generation, and 

 we now add, that the most striking character of their structure 

 renders this consideration doubly weighty in regard to the 

 latter class. The most striking character in the complicated 

 structure of intestinal worms is the immense developinent of 

 their reproductive system^ and this fact alone might well nigh 

 decide the question respecting their spontaneous generation. 

 The argument is this : If these worms have a spontaneous 

 origin, a reproductive system is wholly unnecessary, and if one 

 tape-worm appears spontaneously, all may ; this, in fact, is the 

 more consistent supposition ; and the more so that the inutility 

 of a system does not necessarily imply that it should be wholly 

 wanting ; for we find nipples in male animals and many other 



