SCIENCE AND INDUSTRY. 
(4) That the exudation was caused by tick attacks. 
(5) That cattle ticks only very rarely, and then with the greatest difficulty, 
re-attach themselves while maturing. 
(6) That there is no difference in regard to the rapidity of hatching of eggs laid 
by ticks taken from the two experimental cows and those laid by ticks from other 
eattle. 
(7) That there is practically no difference between the nature of the infesta- 
tion of the so-called resistant animals and that of ordinary cattle during either 
the winter or summer months. 
(8) That the difference in temperature reported by Mr. Hull did not occur. 
It will thus be seen that Mr. Pound disagrees with all Mr. Hull’s claims. The 
latter were in part re-stated in 1915 before the Select Committee of the Legislative 
Assembly, and another claim was added, viz.: that the application of an arsenical 
dip or wash temporarily suppressed the tick-resisting peculiarity. 
Mr. Hull has recently modified, as a result of further observations, certain of 
his claims (Nos. 1 and 3 in this report) to a slight extent, and now states that 
the number of ticks (50-100) given as being carried per year by a _ resistant 
animal is, in many cases, excessive; that some of the ticks, in addition to the few 
that mature, instead of dying whilst very minute, as most of them do, continue 
to develop, but die before undergoing engorgement; that certain cases of apparent 
hereditary transmission has made its appearance in one case in a calf during the 
first year of life. 
Tt appears to us that the most important points to be ascertained are:— 
(1) Whether tick resistance actually occurs, i.e. whether there are cattle 
which, when placed under conditions of natural infestation, do not become infested 
to the same degree as other animals similarly situated. 
(2) Whether the degree of resistance is sufficiently marked so that very few, 
if any, ticks mature on such animals which, as a consequence, do not require 
dipping or’ other treatment to prevent tick worry. 
(3) Whether resistance depends on breed, food, climate, &c. 
(4) Whether the resistant condition (if present) can be transmitted in any 
way. 
(5) Whether an exudation of serum or lymph occurs locally on resistant 
animals, and whether such is merely a form of tick sore. ‘ 
Tick resistance might be manifested by— 
(a) a failure to develop any ticks belonging to a particular species; such 
would be an example of tick immunity; 
(b) a tendency towards light infestation when ordinary controls become 
heavily infested; 
(c) a failure on the part of female ticks to become fully matured or 
engorged in such numbers as on controls when under the same con- 
ditions of climate; 
(d) a failure of such engorged ticks either to lay a normal number of eggs 
or to lay eggs showing a normal percentage of hatchings. 
In regard to (a), we know that some ticks are very restricted in regard to 
suitable hosts, e.g., the cattle tick (Boophilus australis, and related species and 
varieties) thrives on cattle, and occurs naturally on horses and occasionally on 
sheep and certain other animals, but it is essentially a parasite of cattle. Other 
Species are not so restricted, e.g., various species of Iwodes, including our coastal 
scrub tick XY. holocyclus. Some must leave their host to undergo certain stages 
of development, and then must re-attach themselves to some suitable host, which 
may belong to quite a different group of animals, e.g., the red-legged cattle tick 
(Rhipicephalus sanguineus), which is occasionally found on horses, cattle, and 
dogs in south-eastern Queensland. The cattle tick, however, passes through all 
its stages on the one host animal. It is common knowledge amongst graziers 
and dairy farmers that there exists in many herds animals which are more or 
less resistant to tick invasion. For some reason, such beasts are distasteful to 
‘ticks, and, consequently, the larve either do not attach themselves, or else, having 
become attached, they only occasionally develop to maturity. 
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