192 
Theory and Practice of Dipping 
The dipping bath (Fig. 1) is a concrete tank built in the ground into 
which it is sunk to such a depth that the rim of the tank is flush with 
the ground level. The bath measures some fifty feet in length and the 
side walls are inclined outwards in such a manner that while the width 
at the bottom is about two feet, the width at the rim is some four to 
five feet. The end wall at the entrance of the bath is vertical, at the 
exit it is sloped at an angle of about 20° to the horizontal to enable 
the animals to walk out of the tank. Near the entrance of the bath is 
an enclosure in which the stock to be dipped are collected, and from 
this a short entrance race leads directly to the vertical end of the 
tank. The exit slope leads to a draining pen. The bath is filled with 
the dipping-fluid to such a depth as to allow of complete submersion. 
The cattle are driven through the entrance race and jump into the 
bath where for a moment they are completely immersed; they then 
swim down the bath to the exit slope, up which they walk to the draining 
pen where they stand while the superfluous dip drips off and drains 
back into the tank. 
At first there may be some difficulty in persuading the cattle to 
enter the bath, but as they become used to the operation, the difficulty 
lies in checking their eagerness. The process is very rapid and 
economical—400-600 head of stock can be dipped in an hour at a cost 
of of a penny per head. 
The concentration of the dipping-fluid should vary according to 
the interval between each successive dipping, and also the species of 
tick to be killed. The South African ticks may be divided into three 
classes in this respect, of which the Blue Tick ( Boophilus decoloratus) 
forms one; the Bont Tick (. Amblyomma hebraeum), with which may be 
associated the Bont-1 egged Tick ( Hyalomma aegyptium), a second; and 
the Brown Tick ( Rhipicephalus appendiculatus) together with all the 
species of Rhipicephalus which transmit East Coast Fever, the third. 
The ticks of the first class are easily killed and are not now considered 
to be of serious importance. 
The Bont Tick, which is important as the transmitter of Heartwater, 
is most difficult to kill, and the dipping-fluid must be moderately strong 
and an interval of a fortnight between the dippings is sufficient. 
In the case of the Brown Tick ( R. appendiculatus) the life cycle is so 
short that the dipping must be repeated at frequent intervals. For this 
reason, an interval of three days between dippings was adopted, since, 
as Lounsbury (1904) has shown that the minimum period of attachment 
of the adult tick was three days, all ticks attached to an animal must 
