208 The Sledge Microtome. [ April, 
ing a great deal of labor. This is done by putting it after it has 
been in absolute alcohol in a very weak carmine or hematoxy- 
line solution. Either of these may be prepared by diluting the 
ordinary tinctures (Beale’s carmine or Boehmer’s hematoxyline) 
with about six times their volume of distilled water. Carmine 
usually gives the best results. The object must be left from 
twelve to twenty-four hours in the coloring solution, according to 
its size and nature, and then replaced in absolute alcohol for 
twenty-four hours. 
It is sometimes convenient to use chromic acid for hardening 
tissues a little before putting them in the alcohol. In this case 
they cannot be easily colored in toto unless every trace of the 
chromic acid has been removed by frequently renewing the abso- 
lute alcohol, a troublesome process requiring a long time and 
large quantities of spirit. 
The object once hardened, or colored and hardened, as the case 
may be, can be imbedded in paraffine by the following method: 
Place it in pure turpentine for half an hour, then five or ten 
minutes in a mixture of equal parts of paraffine and turpentine 
by weight, warmed so as to be liquid, and afterwards in pure, 
melted paraffine for five minutes. Great care must be taken not 
to have the paraffine warmer than is necessary to keep it liquid, 
otherwise the tissues will be ruined. The object should be 
moved about gently in the paraffine to free it from the turpen- 
tine adherent to its surface. By these processes the paraffine 
penetrates the whole object, giving it the best consistency possi- 
ble for cutting. 
The next step is to pour some paraffine into a little paper tray, 
then lay the object in it, and pour in enough paraffine to cover it 
over entirely, and leave it for half an hour or more to cool, The 
mass of paraffine, when solid, may be taken out, and trimmed 
down with a penknife to such a size and shape as will let it fit 
into the clamp of the object holder of the microtome ; the part 
containing the object must project enough above the clamp to be 
struck by the knife as it is drawn along, in the way above de- 
scribed. 
When the object contains fatty tissue which it is wished to 
examine more closely, it may be imbedded in the so-called trans- 
parent glycerine soap in the way that has already been in us 
several years. 
The sections when made are surrounded by paraffine, and usu- 
ally curl up. They must be taken up with a fine-pointed brush, 
e for — 
