1164 EXPERIMENT STATION RECORD. 



The influence of mammalian and avian tubercle bacilli on the reaction 

 of the culture medium, O. Bang (CcntN. Bait. [etc.]. 1. AM., Orlg., .',3 

 ( 190(1), Xo. 1, piJ. 3Jf-.'i3, fiffs. 2). — As the result of a long series of cultures with 

 tubercle bacilli of different origin it was found that with regard to its reaction 

 on culture media, the avian tubei'cle bacillus behaves very much lilce tlie bovine 

 form. It appears, however, to render the culture medium somewhat more 

 decidedly alkaline. The reaction produced by the human tubercle bacillus may 

 be somewhat changed by altering the supply of oxygen, but the change thus 

 induced is not great enough to bring about a confusion between the bovine and 

 human tubercle bacillus. 



Anthrax and imported animal products, W. Hanna (Puh. Health [Lon- 

 don], 19 {1901), No. 7, pp. Ji39-Ji59). — On account of the interest which attaches 

 to the means by which anthrax is spread, particularly through commerce in hair 

 and hides, the author examined into the records of 21 human cases of anthrax 

 in Liverpool. 



The study of these cases indicates clearly that all workmen should be warned 

 by proper circulars against the possibility of infection with anthrax, and that 

 all foreign hides from suspected countries should be scheduled under special 

 rules and should be imported only in large canvas-covered bales, requiring 

 mechanical handling. It is recommended that the hides be shipped wet rather 

 than dry and that infected material be traced to its source of origin and an 

 attempt made through official channels to secure veterinary . inspection in the 

 locality where the disease originated. 



The persistence of the Texas fever organism in the blood of southern 

 cattle, E. C. Schboeder and W. E. Cotton {U. S. Dept. Agr., Bur. Anhn. Iiidtis. 

 Rpt. 1905, pp. 77-78). — Three southern cows were vised to test -the persistence 

 of the blood parasite of Texas fever. The cows were protected from exposure 

 to the disease during the experiments. It was found that the blood parasite 

 persisted for 10 to 12 years. Apparently excessive infestation with cattle ticks 

 may so reduce the resistance of cattle to Texas fever that an acute form of the 

 disease may develop in cattle which were apparently inmmne and sbnwed blood 

 j)arasites in an inactive condition. 



Notes on the cattle tick and Texas fever, E. C. Schroeder ( ['. »?. Dept. Agr., 

 Bur. Anini. Indus. Rpt. 1905, pp. 49-70). — A resume is given of the life history 

 of the cattle tick. The average time required for a full life cycle is 54 days, 

 and the average length of time for the deposition of the eggs is 7 days. It was 

 determined that adult ticks may be kept without material injury for at least 

 96 days at temperatures below freezing. 



The average incubation period for tick eggs is 25 days, the shortest observed 

 period being 12 days, and the longest 209 days. This time depends largely on 

 the temperature. The eggs may be exposed for several weeks to temperatures 

 below the freezing point without destroying their vitality. On an average, 

 cattle ticks mature in 22 days, the shortest period being 15 days, and the longest 

 40 days. 



Considerable attention was given to a study of the influence of cattle ticks 

 upon cattle aside from being agents in the transmission of Texas fever. In the 

 growth of the cattle tick its weight increases about 10,000 times during the 3 

 weeks. This constitutes a serious drain upon the vitality of infested cattle, 

 some of which are killed outright. Calves become badly stunted as a result of 

 infestation. Pathological changes were noted in the skin about the point where 

 the ticks were attached. The actual weight of ticks which mature and fall off 

 may amount to i oz. to several ounces daily. It was shown that cattle on which 

 from 100 to 150 ticks were daily matured showed in some instances a diminution 



