ove contains practically 0.19 per
cent arsenious oxid when fresh. After use oxidation may set in and weaken
it, but it will not need to be strengthened so long as it tests not less
than 0.175 per cent arsenious oxid.

To make up small quantities for spraying, to each 5 gallons of water
measured out add first 2 fluid ounces (4 tablespoonfuls) of tar stock, and
then 5-1/8 fluid ounces of S-B stock or 2-1/8 pints of boiled arsenic
stock.

The standard strength of bath should be adhered to so far as possible
because its effectiveness against ticks will effect eradication in the
least time and with fewest dippings. But if time is not pressing it is
sometimes best to begin with a lower strength, say 0.14 or 0.15 per cent,
and gradually work up to full strength as the cattle become accustomed to
the treatment. This is certainly a wise method for the individual cattle
owner who is outside the area of cooperative work and who lacks aid and
advice from experts. Weather conditions also need to be considered. Hot or
moist weather is more trying to the cattle than cool or dry weather. The
longer the time needed for the cattle to dry off after dipping, which of
course primarily depends on the proportion of moisture in the air, the more
liable they are to show blistering or other injury through the continued
absorption of arsenic by the skin. The combination of heat and moisture is
particularly bad, and under such conditions it may be desirable, unless
other conditions prohibit, to use the bath somewhat weaker than standard
strength. The following table shows the quantities of arsenic and stock
solutions contained in 100 gallons of bath of different strengths, so that
the quantities necessary to charge a vat of any size at any strength can be
found by simple multiplication.

_Composition of dipping baths._

+-----------+------------------------------+
| Actual | Per 100 gallons of bath. |
| arsenious +------------------------------+
| oxid. | White | S-B | Boiled |
| | arsenic. | stock. | stock. |
+-----------+----------+---------+---------+
| Per cent. | Pounds. | Gallons.| Gallons.|
| 0.05 | 0.42 | 0.21 | 1.3 |
| .06 | .50 | .25 | 1.6 |
| .07 | .58 | .29 | 1.8 |
| .08 | .66 | .33 | 2.1 |
| .09 | .75 | .38 | 2.3 |
| .10 | .83 | .42 | 2.6 |
| .11 |