ON THE EARLY STAGES OF INFLAMMATION 215 
extreme degree of adhesiveness, sticking together indifferently by their edges, 
or any other parts that happen to come first; and if one of the masses be 
stretched so as to break, the separating corpuscles become drawn out into long 
viscid processes, which at length give way in the middle, and each half is drawn 
into its respective corpuscle. 
This remarkable effect cannot be accounted for by the mere viscidity of the 
plasma, which would not make the corpuscles adhere to each other more inti- 
mately than usual, unless they had themselves experienced some change, of 
which, indeed, their altered form is conclusive evidence. Further, if a very 
small quantity of acetic acid be added to the gum before mixing it with the 
blood, the corpuscles will be found to have lost altogether their adhesive char- 
acter, although the mixture may be made viscid to any degree that may be 
desired. A little acid perspiration on the finger appears to prevent entirely 
the formation of rouleaux in a drop of blood taken from it ; but after the finger 
has been washed, the usual appearances present themselves when more blood 
is drawn. Diminished adhesiveness of the red corpuscles is also the earliest 
evidence of the chemical action of tincture of cantharides and croton oil on the 
blood of the frog. A similar effect is produced when a drop of human blood 
is Shed into a little fresh almond or olive oil on a plate of glass, and stirred slightly 
so as to break up the blood into minute drops. On microscopic examination 
of such a mixture, one sees the red discs aggregated as usual in the interior of 
the larger drops; but at their exterior, which is in contact with the oil, and 
throughout the smaller drops, the corpuscles are somewhat altered in form, 
being of less diameter, but thicker, though still in the form of discs, and at the 
same time they are found to have lost every trace of a tendency to adhere to- 
gether ; and when present in a thin layer of blood they stand apart at equal 
distances from one another, as if exercising a mutual repulsion, at the same 
time exhibiting molecular movements. If a drop of blood freshly shed upon 
a glass plate be stirred with a needle in an atmosphere of chloroform vapour, the 
rouleaux will be found to form less perfectly in proportion to the time that the 
chloroform has acted, until, if the period be as long as thirty seconds, the cor- 
puscles will be all cup-shaped, and will exhibit no disposition to aggregate. 
But no effect is produced on the formation of the rouleaux by stirring a drop 
of blood in the same way for a much longer time in an atmosphere free from 
chloroform. The aggregation of the corpuscles is not prevented merely by 
their becoming cup-shaped, and therefore unable to apply themselves to each 
other as usual. For the vapour of caustic ammonia, while it renders the cor- 
puscles cup-shaped, seems rather to increase than to diminish their adhesiveness 
and aggregating tendency, and a temperature of about 32° Fahr. has similar 
