ACALEPH^B. 205 



more easily since it is empty at this place and much enlarged. 1 

 continued to advance the bristle, and, in proportion as it advanced, the 

 polyp hecarne more and more inverted. When it came to the worm, 

 by which the mouth is kept open on one side, and the posterior part 

 of the polyp is passed through the mouth, the creature is thus turned 

 completely inside out ; the exterior superficies of the polyp has become 

 the interior." 



The poor animal would be justified in feeling some surprise at its 

 new situation disagreeably surprised we may add, for it makes every 

 imaginable effort to recover its natural position, and it always succeeds 

 in the end. The glove is restored to its proper form. " I have seen 

 polyps," says Trembley, " which have recovered their natural exterior 

 in less than an hour." But this would not have served the purpose 

 of our experimenter. He wished to know if the polyps thus turned 

 outside in could live in this state ; he had consequently to prevent 

 it from rectifying itself, for which purpose a needle was run through 

 the body near the mouth in other words, he impaled the creature 

 by the neck. 



"It is nothing for a polyp only to be spitted," says Trembley. 

 It is in fact a very small thing, as we shall see, for thus reversed and 

 spitted they live and multiply as if nothing had happened. 



" I have seen a polyp," says this ingenious experimenter, " turned 

 inside out, which has eaten a small worm two days after the opera- 

 tion. I have fed one in that state for more than two years, and it 

 has multiplied in that condition. 



" Having experimented successfully myself, I was desirous of having 

 the testimony of others capable of forming opinions on the subject. 

 M. Allamand was persuaded to put his hand to the work, which he 

 did with the same success I had met with. He has done more, 

 having succeeded in permanently turning specimens which had been 

 previously turned, and which continued to live in their re-inverted 

 state ; he has seen them eat soon after both operations ; finally, he has 

 turned one for the third time, which lived some days, but perished 

 without having eaten anything, although it did not appear that its 

 death was the result of the operation." 



We have said that the Hydra viridis has neither brain, nervous 

 system, heart, muscular rings, lungs, nor liver; the organs of the 

 senses namely, those of sight, hearing, and of smell have also been 



