26 
As my observations upon the developing eggs occupied all my 
time, I was not able to make any record of the temperature 
of the water of the ocean, but during June there w T ere a num- 
ber of cold, windy days and nights, and two hail-storms, and 
on each of the cold days all the embryo which I had in the 
house died. 
Before I close this portion of my paper, I wish to call at- 
tention to some points of general interest, which have sug- 
gested themselves to me during the prosecution of my work. 
At first sight it does not seem possible that an animal which 
is encased in a hard, strong, protecting shell, and which is 
capable of giving rise to several million eggs every season, 
can be in any danger of extermination ; and it seems as if 
the oyster ought to be able to hold its own in the struggle for 
existence, and to increase and multiply in the face of the most 
adverse circumstances. 
It appears wonderful that the waters of the Chesapeake 
Bay are not paved with oysters, and persons who have not 
given much thought to the subject will ridicule the statement 
that there is any need for measures to prevent their extermina- 
tion or the destruction of the natural beds. While the con- 
sumption of oysters was restricted to regions in the immediate^ 
vicinity of the beds, the number of oysters which it would 
pay to gather and put into the market each season from each 
bed was limited ; but with the present facilities for packing 
and transporting oysters, there is no limit to the number which 
can be utilized, and the danger of destroying the best beds* 
grows greater every day, and keeps pace with the increasing 
population and improvements in transportation. 
Those who believe that the abundance of the supply up to 
the present time is sufficient proof that it will continue, will 
do well to reflect upon the facts given in the following table,, 
which I have condensed from a recent book on the oyster, by 
Mobius (Die Austern und die Austernwirtschaft, Mdbius, 
Berlin, 1877, page 67.) He gives a long table, showing 
the number of oysters taken yearly from the Bay of Cancalc,. 
on the coast of Norway, for about one hundred years, and I 
have copied enough from it to show its character : 
