1 Man., 1898.] QUEENSLAND AGRICULTURAL JOURNAL. 211 
Diseases in Animals. 
(TICK FEVER.) 
PROGRESS REPORT ON THE REPRODUCTIVE FORMS OF THE 
WMICRO-ORGANISM OF TICK FEVER, WITH SOME OBSER- 
VATIONS ON THE RELATIONSHIPS AND NOMENCLATURE 
OF THAT DISEASE. (16rn Decemper, 1897.) 
By J. SIDNEY HUNT, M.R.C:S. Eng. ‘ 
| 
ON THE REPRODUCTIVE FORMS OF THE MICRO-ORGANISM OF 
TICK FEVER. 
Tyrp disease amongst cattle called, in Queensland, Tick Fever, has been 
shown to be, beyond question, identical with that which has long been known 
in the United States as Texas or Southern Cattle Fever.* The same disease 
is, almost certainly, prevalent, under different names,t in various other parts of 
the world, notably the Argentine Republic, South Africa, Roumania, and, 
perhaps, Java. Its geographical distribution is therefore very extensive, and. 
its economic importance to the chief cattle-raising countries of the world by 
no means inconsiderable. 
From the standpoint of comparative pathology, moreover, the disease is of 
great interest and importance, because, as will be presently further indicated, 
it has many points of suggestive analogy with one of the most widely prevalent 
kinds of malady that affect mankind—viz., malarial diseases. 
Tt is not here proposed to give any detailed account of tick or Texas 
fever, because this has already been done in a very complete and masterly way 
by Dr. Theobald Smith and ¥. Kilborne,t whose work has, moreover, been 
repeatedly verified both in the States§ and in Queensland.|| In order, 
, however, to make clear the bearing of the observations which it is the purpose 
of this paper to record, it may be convenient to here briefly outline some of 
the more salient features and already ascertained facts in connection with the 
micro-organism of tick fever. 
Theobald Smith, in 1889, discovered that the remarkable bovine disease, 
whose nature had baffled all previous observers,** was due to a blood-destroying 
microparasite belonging to the Protozoa, which he named, from its physical 
characteristics, Pyrosoma bigeminum. He, in conjunction with <F. Kilborne, 
also determined the fact that the cattle tick (Ixodes Bovis) was the agent by 
which, in Nature, the disease is communicated.++ i 
The micro-organism in question invades the blood corpuscles,tf and is also 
to be found free in the serum.§§ In the former situation it is very frequently, 
as its name implies, more or less pear-shaped, and paired.t{{ When free it is 
* Report on Texas or Southern Cattle Fever, by Theobald Smith and F, Kilborne; Eighth 
and Ninth Reports of Bureau of Animal Industry, U.S. Dept. of Agriculture, 1891-92. 
+ For synonyms sce note on page 220 of this Report. ; 
+ Loe. cit. : 
§ Vide Bulletin 37 of Missouri Experiment Station. 
eae on ester Obeeneeng oovernmen reer Oli 1896. z 
| Preliminary Observations on the Micro-organisin of Texas Fever i mi 
M.D. (Medical News, 21st December, 1889). pay ACOA SEAL 
** Previous American literature of the subject, passim, 
+t Loo cit. 
++ Vide Fig. Il. 
§§ Vide Fig. I. 
