RECENT WORKS 01s THE ENTOZOA. 349 



And if this freedom from unpleasant consequences be true of tliat 

 " monstrum horrendum et ingens," as Doeveren* styles the Tcsnia, 

 how much more does it not apply to most of the smaller parasites ? 



In truth, it is a monstrous assumption to regard the occurrence 

 of JEnfozoa within the human body as constituting, per se, an ab- 

 normal state of things. Let us not forget the case of other 

 animals, with reference to the same category. Is the existence of 

 the whole helminthoid group, with its manifold types, displaying 

 such wonderful structures, such wonderful relations to other groups, 

 and to the general conditions of life, to be regarded as an anomaly ? 

 Entozoa, in excessive numbers, or in unusual situations, have indeed 

 proved dangerous, but such dangers are either rare or, if not so, 

 may be met by proper prophylactic measures. No doubt a single 

 BracunculiLS, or a large hydatid, or even a small scolex-cyst in some 

 situations (e.g., Cysticercus celluloses in the eye, as described by Von 

 Grafe) offer exceptions to what has just been said. And the multi- 

 locular or colloid form of hydatid disease which Yirchow and 

 Leuckart have so well explained, demands a special place in the 

 ' genera morborum.' Still, even in these instances, modifying cir- 

 cumstances may occur. Spontaneous disappearance of hydatids 

 is not infrequent. • Dracimculus loay though more than an inch in 

 length, quits, after a residence of years, the eye which it infests, 

 " and thus the disease becomes naturally cured."t Even its larger 

 congener is not always dangerous. " In one case," writes Mr. Busk, 

 *• in which a guinea- worm fully six feet long was accidentally dis- 

 covered lodged in the deep cellular tissure of the leg around the 

 tendo Achillis, and which occurred under our own observation, no 

 morbid symptom whatever was exhibited during life, nor after death 

 was there the slightest appearance of irritation in the surrounding 

 tissue." 



"We might recollect, also, how man is liable to suffer, though in 

 a different way, from his enemies among the non-parasitic members 

 of the animal kingdom. 



It would appear, further, that certain morbid states of the body, 

 due to various causes, render man particularly obnoxious to the 

 attacks of parasites. This seems proved by the fact that numerous 

 JEntosoa of several kinds, having obviously no genetic coni^ection 



* Dissertatio de Vermibus Intestinalibus Hominum, 1753, p. 15. 

 t Cobbold, p. 389, on authority of Guyot. 



