[ 32 ° ] 
limited the proportions of the water and the falts 
in our blood. A degree of latitude in thefe pro- 
portions however feems to be admitted ; for I ob- 
ferved the veficles equally unchanged when mixed 
with a folution of falts confiding of eight drops of 
water to one of the faturated folution, and when 
added to a mixture of fifteen drops of water to one 
of the fame folution. 
Not only the neutral falts in the blood are capa- 
ble of preventing the ferum from diffolving the 
veficles ; but the mucilage or lymph with which 
the ferum is fo much impregnated, feems to con- 
tribute to the fame effebh 
When the veficles have been made fpherical, bv 
ibeing mixed with water, if a fmall quantity of 
pretty flrong folution of a neutral fait be added, 
tthey are immediately fhriveled, a few of them 
•recover their former flat fhape, but the greated part 
are contrabted irregularly into fmaller fpheres. 
When thefe veficles thus recover their fhape, after 
‘having been a fhort time mixed with water, they 
are generally more tranfparent, and appear thinner, 
a part of their fubftance having been difl'olved in 
the water; and thence it is more eafy to diflinguifh 
the little folid particle which is contained in them. 
By this experiment 1 have had the pleafure of con- 
vincing many curious perfons of the compofition of 
this part of the blood, who were not quite fatisfied 
from fome of the other experiments. 
I have mentioned above, and have fhewn in plate 
XII. that thefe veficles are of different fizes in dif- 
ferent animals. I have likewife obferved, that they 
are not all of the fame fize in the fame animal, 
fome 
