50 CIRCULAR 148, U. S. DEPARTMENT OF AGRICULTURE 
top. All measurements should be made only of the space to be 
filled with dip, and not above the dip line. The capacities of the 
various tanks are obtained by a like process. 
Before dipping, the contents of the vat should be well stirred in 
order that the dip may be of uniform strength and temperature 
throughout. The pens, chutes, vat, etc., should be examined for pro- 
jecting nails or any object that might puncture or wound the horses, 
as the dip may injure 
those having fresh 
wounds. 
In dipping wild 
range horses it is nec- 
essary to have a gate 
or bar in the chute to 
prevent the animals 
from piling up in the 
vat. Horses should 
be watered and fed 
from two to four 
hours before dipping, 
and if heated by driv- 
ing they should be 
allowed to cool off be- 
fore entering the vat. 
The head of each 
animal should be 
completely submerged 
for an instant at least 
once while in the vat. 
The head should not 
be held under, but 
quickly ducked with 
a dipping fork and 
released. Two duck- 
ings of the head are 
advisable, especially 
if the animals are 
affected with scabies. 
Care should be taken 
to see that the inner 
surface of the ear is 
well soaked. 
In dipping for lice 
it is not necessary to 
FIGURE 33.—Dipping vat being filled with liquid hold horses in the vat, 
but if they have 
scabies they should be held in the vat two or three minutes. After 
leaving the vat the animals should be held in the draining pens 
until all surplus dip has drained off their bodies. (Fig. 34.) 
Dipping should be finished for the day early enough to dry the ani- 
mals before sunset. 
Before approving a dip for use in official dipping one of the 
requirements of the Bureau of Animal Industry is that there shall be 
