C 321 3 
fome being a little larger than others ; and fome 
diflblve in water more readily than others. In the 
fame fpecies of animals they even differ in fize in 
the different periods of life. In a chicken on the 
fixth day of incubation I found them larger than 
in a full-grown hen, as is reprefented in the plate ; 
and I found them larger in the blood of a very 
young viper than in that of its mother, out of whole 
belly it was taken. I have not however been con- 
vinced from experiments, that there is any differ- 
ence in fize between thofe of a child at its births 
and thofe of an adult perfon. 
In the blood of fome infefls the veficles are notr 
red, but white, as may eafily be obferved in a lobfter 
(which Linnteus calls an infect); one of whofe legs.-, 
being cut off, a quantity of a clear fames flows - 
from it ; this, after being fome time expofed to the 
air, jellies, but lefs firmly than the blood of more - 
perfect animals. When it is jellied, it is found 
to have feveral white filaments; thefe are princi- 
pally the veficles concreted, as I am perfuaded from , 
the following experiment. 
Experiment IV. If one of the legs of a lobfter 
be cut off, and a littleof the blood be catched upon a t 
flat glafs, and inftantly applied to the microfcope, it; 
is feen to contain flat veficles that are. circular, like 
thofe of the common fifh, and have each of them <, 
a. lefler particle in their center as thofe of other ani- 
mals. But there is a curious change produced in ■ 
their fhape by being expofed to the air ; . for foon . 
after they are received on the glafs, they are cor- - 
rugated ; or from a flat fhape. are changed into re- * 
gular fpheres, as is reprefented in plate XII. N° XII. „ 
This: , 
