THe Microscore. 69 
Bizzozero calls them blood-plates, and this is by far the prefer- 
able term. 
“On account of the quickness with which they are destroyed 
after the blood has escaped from the vessels, it is necessary to 
make use of certain preservative liquids which have the power 
of fixing these corpuscles in their normal shape. The solution 
recommended by Hayem is composed, of water 200 parts, sodium 
chloride 1 part, sodium sulphate 5 parts, and mercuric chloride 
.50 parts. Bizzozero recommends a .75% solution of sodium 
chloride, to which some methyl! aniline violet has been added. 
Osmic-acid solution, 1%, may also be used. To obtain good 
specimens of the blood-plates, the following method is suggested 
by Laker. <A drop of preservative liquid is placed on the slide, 
and a drop of blood on the cover-slip, and the slip laid quickly 
on the slide, so that the two drops come in contact. As many 
as possible of the red corpuscles are then drained off by means 
of a piece of filter-paper applied to the slip on the side opposite 
to the drop of preservative liquid; or the two drops may be 
placed on the slide, and the cover-slip laid on from the slide of 
the preservative liquid. The one precaution which it is neces- 
sary to observe is to lose as little time as possible in transferring 
the blood to the preservative liquid. 
Obtained in this way, the blood-plates of the mammal are 
small, non-nucleated, discoid bodies from one-fourth to one- 
half the size of the red corpuscles. Hayem states that they are 
bi-concave, like the red corpuscles, and that many of them have 
a slight greenish or yellowish color due to the presence of 
haemoglobin. Bizzozero, on the other hand, maintains that 
they are perfectly colorless and not bi-concave. 
They are about forty times more numerous than the white 
corpuscles. In their general behavior toward reagents they 
resemble the nucleus of the white corpuscles, according to 
Laker. Hayem states his reasons for believing that they are 
finally transformed into red corpuscles. They play a most im- 
portant part in the congulation of the blood. In brief, it may 
be said to be proven that there is, around a thread, first, a 
deposition of these plates ; second, their fusion into a granular 
mass; and third, the formation of fibrine. The origin of 
thrombi in blood vessels is attributed to the destruction of these 
corpuscles. 
