ORGANIZATION AND GrowTH 225 
about 200 per cent., is added to the sea-water, a remarkable 
phenomenon occurs: large pieces of protoplasm escape 
from the Tubularie without losing their form. They are 
surrounded by a transparent membrane which is formed per- 
haps through their contact with the sea-water. I saw a 
piece 1-2 cm. long escape from a Tubularian in this way. 
4. That an increased absorption of water by the tissues 
favors regeneration when it does not exceed a slight amount; 
while a greater absorption is harmful, might seem contradic- 
tory. But itis an entirely general and well-known fact that 
when water enters cells in too large quantities it acts as a 
poison. Hoppe-Seyler, for instance, attributes the death of 
frozen plants which are thawed out too rapidly to the fact 
that ‘‘in freezing, the water separates to a large extent from 
‘the solids and collects in crystals. When thawed out rap- 
idly, the particles of solid matter lying nearest these crystals 
are flooded with water.’” 
5. The pieces regenerating in the highly dilute solutions 
often show changes which indicate the great turgidity of 
the tissues, in consequence of the abnormally great absorp- 
tion of water. Before the polyp is formed, globular excres- 
cences appear at the cut ends, and the new polyps are thicker 
and much more nearly globular than the normal polyps. 
The opposite phenomena are noted in the strongly concen- 
trated salt solutions, in which polyps remain exceedingly 
small. 
6. In conclusion I wish to give a few figures on the rela- 
tion between regeneration and the absorption of water. In 
order not to repeat what has already been said, I shall take the 
figures from experiments in which the concentration of 
the sea-water was increased by the addition of sodium 
chloride, or decreased by the addition of fresh water (Serino 
water). According to Forchhammer, the amount of salt 
1 HoppEe-SEYLER, Physiologische Chemie (Berlin, 1877), p. 30. 
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