* 1 Mar., 1899.] QUEENSLAND AGRICULTURAL JOURNAL, 223 
shipped to the experiment station and divided into two lots. our of these 
cattle with the ticks upon them were placed in one field with thirteen native 
animals. Of these native cattle ten, or 76°8 per cent., died with Texas fever. 
From the three southern cattle in the second lot, the ticks were caretully 
picked by hand on successive days until no more developed upon them. They 
were then put in a field with four native animals, none of which contracted the 
disease from them. 
This preliminary experiment having resulted favourably to the tick theory, 
other similar experiments were made later in the same summer ; and in all 
cases the native cattle exposed to southern cattle with ticks contracted disease, 
while those exposed to southern cattle from which the ticks had been carefully 
picked by hand remained healthy. A variation of this experiment was made 
the same year by placing some native cattle in a field to which no southern 
animal was ever admitted. In this field ticks picked from the southern animals 
were scattered over the grass. ‘Three ott of four animals in this field 
contracted Texas fever. i 
In the following year (1890) these experiments were repeated. It had 
been clearly shown that the ticks spread the disease, and the main points now 
were to ascertain how this was done and whether there was any other means of 
transferring the contagion. A further variation of the experiment was made 
by hatching in the laboratory the eggs of southern ticks and placing the young 
ticks upon native cattle, and it was thus shown that the young ticks are 
capable of producing the disease. 
It is not necessary to go into details relative to the numerous experiments 
that were made to clear up the manner by which this disease is carried and. 
spread. The facts bearing upon this aspect of the question will be briefly 
stated in order that the reader may have an intelligent understanding of the 
measures that are required in the way of prevention. : 
The large ticks which are seen attached to the skin of cattle are females. 
The males always remain small, about the size of a pin’s head. The females 
become attached when small, mature rapidly during warm weather, and much 
more slowly in cold weather, are fertilised by the male, finally drop to the 
earth, lay their eggs and die. The malesare said to drop from the cattle about 
the same time as the females, and to die within a day or two; though on 
account of their small size they are more difficult to follow, and there is less 
certainty in regard to them. 
The females produce about 2,000 eggs, which are laid in the course of a 
week after they drop from the cattle. The eggs hatch in about three weeks in 
midsummer; in cooler weather four or five weeks are required; while if laid 
early in the spring they will not hatch until warm weather, even if several 
months intervene. The young ticks, although active, do not travel far, but 
climb up the first grass or herbage they encounter, and cling to any animal 
which brushes against them. When they get upon cattle they soon attach 
themselves to the skin, making a puncture and sucking blood for their susten- 
ance. In from ten to fifteen days in summer after the cattle become infested 
with these young ticks the symptoms of fever are observed. In cool weather 
the disease develops more slowly. 
Summing up the life history of the tick, it may be said that the adult females 
are mature and drop to the earth in three weeks or longer (according to the 
weather) after they get upon the cattle. The femates are about a week in 
laying their eggs and then die. The young ticks hatch in three to four weeks 
in summer, and may live a long time, probably until cold weather, without 
food and without developing, if they fail to come in contact with cattle or 
other animals favourable to their existence. 
hese facts not only explained many of the mysterious features of Texas 
fever, but they indicated that by destroying the ticks upon the southern cattle 
the danger of spreading the disease might be removed, 
