the Origin of Intestinal Worms, 327 



ture. Their spontaneous origin may appear somewhat more 

 plausible than that of more complicate organisms ; it is not 

 more so in reality. 



Sect. 5. Which modification^ however ^ did not prove correct 

 in a single instance.-^On one occasion an excellent opportu- 

 nity was afforded me for observing whether there was any gra- 

 dual degeneration into an intestinal worm ; and I made the best 

 possible use of it. In nearly all the Cotti scorpii (fig 1, Plate vii., 

 in 98 out of 102 which I examined) may be found a greater or 

 a lesser number of Bothriocephali punctati, all of which were 

 attached, by the foremost part of the head to the mucous 

 surface of the appendices pyloricae. I found the size of these 

 worms very different, according to the greater or smaller 

 number of joints connected with the head. The smallest were, 

 but one-third of a line, had no joints, and consisted only of the 

 head. These heads were almost concealed between the valves 

 or villi, attached to the mucous surface, and the suggestion 

 forcibly occurred to my mind, that these heads might be no- 

 thing more than degenerated valves like corns or tubercles. 

 A more accurate examination, however, soon banished this 

 idea. Nowhere could I find any morbid alteration of the 

 valves, which indicated any thing like an intermediate state 

 between a valve and a bothriocephalus ; and every protuber- 

 ance was, with the greatest facility, ascertained to be a valve 

 or a worm, with its individual characteristics of form, struc- 

 ture, colour, attachments, &c. 



CHAP. III. IS COMPLETE ORGANIZATION COMPATIBLE WITH THE 



SUPPOSED SPONTANEOUS GENERATION ? 



Sect. 1. The question answered in the affirmative by Profes- 

 sor Burdach. — These animals, which are held to arise sponta- 

 neously, have a highly complicated structure, in which a har- 

 mony as perfect as that which characterizes organisms in ge- 

 neral prevails. To most this must appear a startling proposi- 

 tion. Let us see how the illustrious Professor Burdach, en- 

 deavours to make it plausible. He remarks (Physiologic, 2d 

 edition, vol. i. page 12), *' By the discovery of the more com- 

 plicated structure of the infusoria, the hypothesis of equivocal 

 generation is in no respect refuted a priori ; for it is in gene- 



