338 
BULLETIN OF THE BUREAU OF FISHERIES 
At the New York State Fish Hatchery at Cold Spring Harbor, Long Island, the females are not strip- 
ped but are allowed to deposit the eggs. The egg clusters are gathered and passed through a sieve 
to separate them from one another. They are then hatched in regular lobster hatching jars sup- 
plied with fresh water. In this place the eggs are laid in about 10 days during the last half of 
March or the first half of April. The water supplied to the jars is quite cold and the mortality of 
the eggs is not as great as in the natural streams of the locality. 
“ However, I found in eggs taken from the hatching jars or from local streams during two con- 
secutive seasons, about one embryo in a thousand with abnormal eyes. The cause of this abnor- 
mality has not yet been found; however, it may be remarked that the water contained an unusually 
large amount of carbon dioxide. The fresh water of Cold Spring Harbor comes from deep springs 
or artesian wells and is charged with this gas. Also I found various poisonous substances to produce 
this abnormality in Fundulus embryos. 5 
There is a large mortality among these eggs when hatched in the tap water of New York City, 
due to the higher temperature and impurities. They hatch better in water redistilled in glass or 
quartz. 
The eggs before being laid contain considerable amounts of sea salts and have an osmotic 
pressure equal to about half that of the sea. I was interested in determining whether the salts 
diffused out of the egg when laid in fresh water, as seems to be the case with frogs’ eggs, or whether 
they were retained, as I found to be true of the eggs of the marine killfish ( Fundulus heteroclitus) . 
Thirty grams of eggs were soaked 14 hours in 250 grams of distilled water. The water was 
then analyzed and found to contain only two one-thousandths of a gram of common salt. It is 
evident that most of the salts are retained by the eggs. 
Since the eggs retain the salts in the same way that the adult fish does, it would seem prob- 
able that the eggs would live better in salt water than in fresh water. From the experiments with 
other marine bony fishes, it is probable that the smelt would live indefinitely in more or less diluted 
sea water, but not in fresh water, although they are normally in fresh water during the short 
breeding season. 
I placed smelt eggs in sea water and in sea water diluted with various proportions of water 
redistilled in a quartz still. The eggs in sea water developed for three or four days and then died. 
Eggs in one-half sea water (which is of about the same salt content and osmotic pressure as the blood 
of the mother) , developed much better than in fresh water. This is probably due to two causes: 
First, the salt in the water being of the same concentration as the salt in the egg, any loss of salt 
from the latter is prevented. Second, the growth of mould (Saprolegnia) is retarded by the admix- 
ture of sea water. Even }/% sea water preserved the life of the eggs better than fresh water. 
It is suggested that in the hatching of smelt eggs, when the mortality is considerable, that the 
jars be supplied with a mixture of sea water and fresh water in the proportion of one part of sea 
water to from one to four parts of fresh water. The water might be mixed by simply connecting 
the salt and fresh water pipes to the pipe leading to the hatchery by means of a T joint. Care 
should be taken to maintain a regular flow in both pipes, and the flow of the sea water should 
never exceed that of the fresh water. The proportion of sea water should be gradually reduced 
just before the time of hatching, as the eggs hatch better in one-fifth sea water than in one-half 
sea water. Perhaps it might be more convenient to reduce the proportion of sea water to zero 
before the eggs hatch. 
I am indebted to Mr. Walters, superintendent of the New York State fish hatchery at Cold 
Spring Harbor, Long Island, for the material on which these experiments were made. 
From the department of anatomy, Corneli University Medical College, New 
York City, April 4, 1913, McClendon sent in an additional note on the same subject, 
which follows: 
This year I installed apparatus for circulating brackish water (and fresh water for a control 
experiment), using miniature hatching jars. However, the expense of keeping the temperature low 
in this laboratory would have been great and if exact data are to be obtained experiments should be 
made at Cold Spring Harbor. 
1 McClendon, J. F.: An attempt toward the physical chemistry of the production of one-eyed monstrosities. American Jour- 
nal of Physiology, Vol. XXIX, No. Ill, Jan. 1, 1912, p. 289. Boston. 
