206 
THE OCEAN WORLD. 
recorded his observations on some of these animals of smallest dimem 
sions. He limited himself even to two sets of experiments : he turned the 
fresh-water polypes outside in, and he multiplied it by cutting it up’ 
These experiments upon this little creature, which few persons h»4 
seen, have sufficed to secure immortality to his name. Trembley w* 19 
tutor to the two sons of Count de Bentinck. He made his observe 
tions at the country-house of the Dutch nobleman, and he had, as 
assures us, “frequent occasion to satisfy himself, in the case of bi p 
two pupils, that we can even in infancy taste the pleasures de' 
rivable from the studies of Nature !” Let us hope that this thought 
uttered by a celebrated naturalist, who spoke only from what he kne^ 
himself, may remain engraved on the minds of our younger readers. 
Trembley established by his observations, a thousand times repeatedr 
that Hydra viridis can be turned outside in, as a glove may b e > 
and so completely that what was the external skin of the zoophyh- 
becomes its internal skin, and this without injury to the animal, which 
a day or two after this revolution resumes its ordinary functions. Such 
is the vitality of these little beings that the external skin soon fulfill 
all the functions of a stomach, digesting its ibod, while the infesting 
tube expanding its exterior performs all the functions of an extern^ 
skin ; it absorbs and respires. But we shall leave Trembley to relab 
his very remarkable experiments. “ I attempted,” he says, “ for tb f 
first time to turn these polypes inside out in the month of July, 174k 
but unsuccessfully. I was more successful the following year, having 
found an expedient which was of easy execution. 1 began by giviu£ 
a worm to the polype, and put it, when the stomach was well filled 
into a little water which filled the hollow of my left hand. I pressed 
it afterwards with a gentle pinch towards the posterior extremities 
In this manner I pressed the worm which was in the stomach again 9 
the mouth of the polype, forcing it to open — continuing the pinching' 
pressure until the worm was partly pressed out of the mouth. "Wh el1 
the polype was in this state I conducted it gently out of the waten 
without damaging it, and placed it upon the edge of my hand, which 
simply moistened, in order that the polype should not stick to it- 
forced it to contract itself more and more, and, in doing so, assisted # 
enlarging the mouth and stomach. I now took in my right hand ,l 
thick and pointless hoar’s bristle, which I held as a lancet is held m 
bleeding. I approached its thicker end to the posterior extremity of k lt 
