1 Aprin,1902.] QUEENSLAND AGRICULTURAL JOURNAL. 293 - 
the Federal authorities may work hardships in individual cases, there can be no 
doubt that it is absolutely necessary to preserve the cattle industry of the United 
States. Were southern cattle allowed unrestricted movement north and west 
during the spring, summer, and fall, these regions would be annually decimated 
in cattle, and the industry ruined. Under the quarantine regulations, southern 
cattle must be shipped by rail or steamer direct to the slaughtering-places, 
or be held in quarantine till all ticks drop off. The cars or boats must be 
thoroughly cleaned or disinfected after the ticky cattle are discharged. Were the 
cattle driven, as in the olden times, the ticks would be scattered along the trail 
and infect any and all cattle passing by, unless the weather were sufficiently ~ 
cold to kill them by freezing. All cattle raised in the country lying south of 
the so-called Texas fever line, or, in other words, all cattle which from birth, 
have pabpores successive crops of ticks, possess a certain amount of immunity 
against the fever. Therefore, southern cattle are generally immune to Texas 
fever. However, Texas fever probably kills more southern cattle than any other 
disease, because, when the acquired immunity is not backed up by a strong 
constitution, or when the animal gets ‘“‘ out of condition,” it loses the power to 
withstand the infection, and then succumbs to the disease when a heavy infes- 
tation of ticks occur. Experiments have shown that two or three hundred ticks 
are a suflicient number to cause the disease. Our stockmen know that many 
times this number can be counted on animals which are considered only 
moderately infested. It has been noticed that the first crop of ticks in the spring 
is not as virulent as succeeding crops. This would indicate that the crop of ticks 
hatched from the egg which wintered over from the previous season either carry 
the parasite in a weakened condition, or in an undeveloped stage, or that it is 
necessary for the ticks themselves to become reinfested by sucking the blood of 
southern animals which are permanently infected with the germ of Texas fever. 
Experiments made by the Bureau of Animal Industry show a southern animal 
may be carried north and kept there, free of ticks for many years, and yet be 
capable of producing Texas fever, if some of its blood be injected into a northern 
susceptible animal. 
The life history of the cattle tick is briefly as follows, according to Dr. 
Cooper Curtice :—The ripe female falls off the cattle and lays eggs for two 
weeks, when hatching begins, which occupies three weeks, more or less, 
according to the temperature. The young ticks, if opportunity occur, attach 
themselves to passing cattle and remain on them for three or four weeks, by 
which time, they in turn have reached the adult stage, or are ripe, and fall off. 
The young ticks may live for nearly a year under favourable conditions of 
warmth and moisture, or the eggs may not hatch out for three months in the 
absence of these. They finally die, however, of starvation if they can find no 
cattle, as they cannot live upon vegetable food, nor can they grow to the adult 
size except when nourished by the blood of cattle. When first hatched out 
ticks are almost too small to be seen by the unaided eye. Certainly it would 
be difficult to find them. Therefore, when the ticks have developed in size 
sufficiently to be found, even upon rather close inspection, they have probably 
infected the animal. ‘Ticks are carried from place to place by cattle; they 
never crawl far away from the place where they are hatched. Bunches some- 
times may be found upon the end of a blade of grass, and be blown some 
distance, or be carried by other means. ‘They have never been known to cross a 
fence where the bottom rail rested upon the ground. One field may, therefore, 
be infested and the other not. Only the young ticks can attach themselves to 
animals, the old ones being unable to crawl against the hair. 
After the foregoing statement concerning Texas fever and its cause, the 
question of most importance to the stockman of Florida is what means can be 
adopted in order to safely and profitably bring the improved cattle from the 
north and west here for breeding purposes. Probably no southern State is 
more dangerous to such animals than Florida, because the climate is rarely 
cold enough to kill off the ticks. The infective agent is then with us at all times. 
It is known that young calves, while they may take the disease, have it in 
-amild form. This applies to the southern as well as the northern calf, and it 
