682 EXPERIMENT STATION RECORD. [Vol 40 



"Rabbits suffering with Eupatorium poisoning usually manifest the first 

 symptoms on the third or fourth <lay (ether-chloroform-ammonia extract). They 

 refuse to eat, sit humped up, eyes half closed, and often keep the body swaying 

 from side to side; the respiration is usually shallow, rapid, and jerky; on the 

 following day (fourth or fifth) a flaccid paralysis of the head, neck, and front 

 legs ordinarily develops; this is followed by complete prostration and death in 

 24 to 36 hours. 



"The principal pathologic changes occur in the kidney, liver, and heart, 

 where fatty degeneration and hyperemia arc very marked. Poured agar plates 

 made from the heart blood, liver, and kidneys were invariably sterile. 



"It is not intended to claim that all cases <.f disease with the symptoms of 

 trembles or milksickness are due to the Ingestion of the toxic substance present 

 in Eupatorium leaves. Jordan and Harris have shown ill. S. EL, 21, p. 783) 

 that a disease with similar, if not identical symptoms, occurs in a region in 

 New Mexico where Eupatorium is not present." 



Tick control work, J. O. F. SoHNS (Dept I.nmlh.. Xijr. c» Handel [Hutch 

 East Indies}, Veeartsenijk. Meded., No. 26 [1918), pp. /•". pis. 8).— A discussion 

 of control work with ticks in Dutch Bast Indies, including plans tor dipping 

 vats. 



The spinose ear tick and methods of treating infested animals, M. I mis 

 (U. S. Dept. Agr. t Farmers' Bui. 980 {1918), /-/.. 8, figs, p.— A brief summary 

 of information on the life history and habits of Ornithodoros megnini is first 

 given, followed by recommendations as to treatment, based upon Investigations 

 conducted by the Bureau of Animal Industry of this Department 



The investigations have shown that dipping in any of the known dips is 

 not effective in killing the ticks or causing them to leave the ears. The rem- 

 edies commonly recommended, such as Maud oils, crude petroleum, various 

 dips, etc., are not effective and they are of use only as vehicles for other 

 remedies. Kerosene and gasoline, which have been used by live stock growers 

 in infested areas for a number of years in treating animals for ear ticks, will 

 kill the ticks, but they cause blistering of the tender skin lining tin- ear pas- 

 sages and may produce deafness, especially in horses <>r dogs. As both kerosene 

 and gasoline evaporate rapidly, they offer no protection againsl immediate 

 reinfestation. Chloroform, either undiluted or mixed with bland oils, used 

 in the ears is effective' hut affords no protection against reinfestation. 



An effective remedy againsl ear ticks has been formulated by the Bureau 

 of Animal industry and thoroughly tested during field Investigationa -Tins 

 consists of a mixture of two parts by volume of ordinary commercial pine 

 tar and one pari by volume of cottonseed oil. "in mixing the Ingredients 

 add the cottonseed oil to the pine tar ami stir until a uniformly smooth mix- 

 ture is obtained. When the weather is cold the pine tar and cottonseed oil 

 should be warmed so they will mix readily and How freely, but they should 

 not be heated more than is necessary. The mixture will remain uniform for 

 a long time without separation or deterioration. It is relatively Inexpensive, 

 easy to prepare, and when properly applied it kills the ticks but does not in- 

 jure the animals. It may be used on any species of domesticated animals." 



"Cottonseed oil is a fairly good solvent for earwax. and the mixture pene- 

 trates ordinary loose masses of earwax and ticks, but it will not penetrate 

 the hard masses. It not only kills all ear ticks with which it comes in contact 

 but being of a sticky consistence it remains in the ears and protects the ani- 

 mals against reinfestation for aboul 30 days." When properly used one appli- 

 cation of the pine-tar-cottonseed-oil mixture is usually sufficient to kill all ticks 

 in the ears of the animal at the time of treatment. 



