WARM-WATER MACERATION TANK. 61 
they will appear to be ready before the grease and blood 
have quite left them. If by accident the water has been 
allowed to get too hot—anything above 95° Fahr. being 
too hot—cold water should be added to reduce it. For 
this purpose also there is a tap from the steam escape by 
which we draw off the hot water, while adding cold to 
the cistern. 
The water should be — regularly, say once a week, 
- if there are many animals in the tank. If a large animal be 
put in, the water should be changed daily for the first three 
days, until most of the blood is removed, for bones are never 
a really good colour if left in water with a quantity of blood 
and grease. For this reason the tank should be examined 
every morning, and all floating grease skimmed off, and 
after emptying it should have a scrub down, and all grease 
and scraps should be cleared out. Of course all bones are 
not the same colour, and one does not want to get them 
white (except snakes and birds), a good cream is the 
average colour; strange to say, many bones that are 
positively black in maceration turn out of the best colour. 
The tank has a lid made of the same kind of boards as 
the sides, battened together and hinged. It might have 
been made of lighter wood, but being strong it serves for 
a good table. When we first used the tank we had move- 
able partitions, each with a semi-circular piece cut out, 
and perforated zinc put in to let the water pass through, 
but we found them very inconvenient when we had many 
large animals in. Afterwards, although there is little risk 
of confusing the bones of different animals, we used, 
when there were more than one of the same kind of 
animal in, to tie all the parts of each individual together, 
but we found when the phalanges and smaller bones 
dropped off it took a considerable time to sort them. 
Finally we had perforated zinc boxes made, which have 
