372 
with the existence of a pellicle having no definite inner 
boundary, and similar to such a scum or pellicle as forms on 
the surface of a cooling mass of jelly. 
7. Effect of isolation from the plasma (a) by adhesion to a 
foreign body (b) by mixture with salad oil.—A very strange 
phenomenon (not hitherto described) is seen when some of 
the corpuscles of the frog’s blood become separated from the 
plasma through adhesion to the glass cover on which they 
are placed, and the drainage away from them of the liquid 3 in 
which they usually float. 
Such corpuscles may often be observed in using the gas- 
chamber, since the drop of blood is in contact with only 
one surface, not between two, as in the case of an ordinary 
slide, and they may be seen thus before any appreciable desic- 
cation has taken place. They entirely lose their oval form, 
and have a tendency to run together, forming polygonal 
mosaic works. 
By pressing a drop of blood into a small drop of salad oil, 
numbers of the corpuscles may also be obtained isolated from 
the plasma, and floating freely in the oil. The ready way in 
which the corpuscles float into the oil, whilst the plasma, of 
course, does not mix with it, seems to indicate a condition 
of the outer wall of the blood-corpuscle, which is not that 
of a membrane simply moistened with water. Both human 
and frog’s blood-corpuscles, when thus passed into oil, lose 
their normal shape. Those of the frog run together, and 
become very closely adpressed in small groups, and some 
lose their hemoglobin, which seems to be taken up by the 
oil (see fig. 4). The human corpuscles lose their biconcave 
character, and become more nearly spherical or polygonal 
when adhering together in masses (see fig. 21 a), By tapping 
the covering-glass I have seen the frog’s corpuscles pass 
readily from the oil back into plasma, and vice versd; but I 
am not sure whether, after they have once lost their oval 
form in the oil, they can resume it on re-entering the 
plasma. 
The effect of isolation from the plasma by means of oil 
is interesting in connection with the views of Dr. Norris! on 
the cause of the formation of the rouleaux of red blood-cor- 
puscles, and deserves further investigation. 
8. Effect of water in minute quantities gradually added (by 
vapour).—By means of his hot plate, consisting of a small 
glass-bottomed well, surrounded by a copper ring connected 
with a copper wire, which can be heated, Stricker was able 
to study the effect of minute quantities of water on the cor- 
1 © Proceedings Royal Society,’ vol. xvii. 
