272 THE MICROSCOPICAL NEWS, 
of any food, after which they grow and bud freely according to 
the food given. I have been in the habit of feeding them daily, 
thus preventing their destroying more than they could eat. My 
experience in dividing the Hydra has been to me exceedingly in- 
teresting. Three years ago I determined to test, by practical 
experiment, the truth of what had been written as to the wonderful 
healing powers of this polype. For some time I had no success, 
although I carefully cut my sections, but had the mortification to 
see them simply slough away. Further experiments revealed the 
cause of failure. Changing the water either before or after the 
division is fatal to success. Weak or sickly Hydra will die ina 
few hours after division if the weather is cold. But if a well-fed 
and vigorous Hydra be cut into sections, and the parts are placed 
back into the same water either in a watch glass or a small bottle 
(I prefer the latter) and the room is not allowed to get cooler than 
about seventy degrees, each section might become a perfect Hydra. 
I say “might” advisedly, for I find the division of Hydra a very 
difficult operation, and one that requires great care and patience ; 
and with all the care and patience, that eighty per cent. will die. 
May and June as the best months for reproducing the lost parts. 
At that time Hydra are the most vigorous, and bud freely ; in fact, 
I prefer to divide those which have very young buds. Placing 
them upon a fine cardboard in a drop of water, I cut them with a 
fine scalpel into slips as you would a plant, or I simply cut through 
a part only of the polype. The cut parts take from three to four- 
teen days, and even more, to become perfect,—that is, before they 
reproduce their lost parts,—or they may live for a few days and 
then disintegrate. The production of a perfect Hydra from a 
single tentacle requires the longest time ; to reproduce a new head 
from the foot part requires a shorter time ; and that which perfects 
itself the quickest is the head, which in a few days will have acquired 
a small body with fully grown tentacles. 
The following dissections I have successfully repeated several 
times. First—cut off head of Hydra. Second—cut head into seven 
sections, each section having one tentacle. Third—cut through 
head and stomach, but not through the foot. Fourth—cut through 
foot and stomach, but not through the head. Fifth—cut off single 
tentacles, no part of the body being attached. Sixth—cut the 
body lengthwise into two distinct parts. Seventh—cut off the 
suctorial disc. This took about the same length of time as the 
tentacle to become perfect. Besides these experiments, I have also 
divided Hydra in various other ways. 
One of the most curious and difficult experiments upon the 
Hydra is to turn one inside out. This is a feat the animal will 
sometimes perform of its own accord. Placing a Hydra in a drop 
of water upon a cardboard, I forced a fine instrument through the 
