.91 | .46 | 2.8 |
| .12 | 1.00 | .50 | 3.1 |
| .13 | 1.08 | .54 | 3.4 |
| .14 | 1.16 | .58 | 3.6 |
| .15 | 1.25 | .63 | 3.9 |
| .16 | 1.33 | .67 | 4.2 |
| .17 | 1.41 | .71 | 4.4 |
| .18 | 1.49 | .75 | 4.7 |
| .19 | 1.58 | .79 | 4.9 |
| .20 | 1.66 | .83 | ... |
| .21 | 1.74 | .87 | ... |
| .22 | 1.83 | .92 | ... |
| .23 | 1.91 | .96 | ... |
| .24 | 2.00 | 1.00 | ... |
+-----------+----------+---------+---------+

As dipping goes on the bath naturally needs replenishing, and its strength
probably needs correction from time to time. Full directions on these
points may be found in Farmers' Bulletin 1057.

_Prepared dips._--Proprietary arsenical cattle dips appear now to have
passed the experimental stage and to have become established as reliable
and useful products. At any rate this can be said of the brands which have
received permission for use in official dipping in place of the homemade
dip. The formulas and standard samples of all such brands are in possession
of the Bureau of Animal Industry and the manufacturers are required to
guarantee that their products as placed on the market will be kept up to
standard and that all requirements of the bureau will be observed. Like the
homemade dip they all contain sodium arsenite as the active tick-killing
agent. They do not all contain pine tar, because that substance is
difficult to blend into a highly concentrated product, but they all contain
some other substance or mixture of substances of such character and in such
quantity as field trials have proved will produce the same effects.

They are not regarded as any more effective or any milder on the cattle
than properly prepared homemade dips. None the less they are undoubtedly
safer for general use because they offer decidedly fewer opportunities for
making mistakes in the quantities used or in the operations gone through
and also fewer chances for accidental poisoning or other injury from the
handling of powerful chemicals. Whether their higher cost is sufficiently
outweighed by these considerations is necessarily a matter for individual
decision.

_Precautions in the use of arsenic and arsenical dips._--The fact that
arsenic is a violent poison is