826 EXPERIMENT STATION RECORD. 



without danger. It is concluded that the blood of young immune animals under 18 

 months of age is not reliable for immunizing cattle. The blood parasites of Texas 

 fever may remain in the blood of an adult immune animal for more than 3 years. 



With regard to the method of tick infestation it was found that, with native calves, 

 it requires an infestation of from inn to 150 ticks to produce a definite fever reaction. 

 Apparently, therefore, if calves are infested at the rate of from 50 to 75 ticks every 

 2 weeks they may be gradually immunized without suffering much harm. It is 

 recommended that calves on infested pastures should be watched so as to prevent 

 their carrying more than 75 to 100 ticks at any time. 



Dipping experiments, S. T. Amos (Natal Agr. Jour. <in<J Min. Jlec, 7 (1904), No. 7. 

 pp. 718, 719) . — Numerous dipping experiments were made with Deinuth'.s dip and 

 Laidlow's tobacco dip, for the purpose of testing the valueof these dips in destroying 

 ticks on cattle. The immediate effects of dipping were quite favorable, a large per- 

 centage of the ticks apparently being destroyed. Later, however, it was found that 

 the small brown tick had suffered very little and the female ticks were laying fertile 

 eggs. 



The dips were again tested in a stronger solution, but when even twice the ordi- 

 nary strength was used a large percentage of the ticks withstood the effects of the 

 treatment. The dips themselves are regarded as objectionable on account of the 

 irritating effects and their disagreeable odor. 



Cattle scab, L. Van Es ( North Dakota Farmer, 5 (1904), No. 12, pp. 7-9, figs. 8). — 

 A description is presented of the seal) mite which causes this disease and also of the 

 symptoms as they usually present themselves. Cattle scab is quite prevalent in the 

 western part of North Dakota, and dipping has become necessary to prevent the 

 development of the disease. Detailed directions are given for the preparation of dip- 

 ping vats or chutes for use among both large and small herds. The dip most gener- 

 ally recommended contains sulphur and lime, and should be applied at a temperature 

 of 105 to 110° F. 



Experience with the new milk fever treatment, 0. L. Dobson (Nebraska 

 Farmer, 36 (1904), No. SO, p. 876). — The author gives the history of a case of milk 

 fever in which the air treatment was applied by means of a very simple apparatus. 

 In the place of the usual glass or metallic tube the hollow portion of a turkey feather 

 was used, and this was attached to an ordinary bicycle pump and the air forced in. 

 Recovery took place without any complication. 



Oxygen treatment in parturient apoplexy, F. R. Whipple (Amer. Vet. Rer., 

 27 (1904), N<>. 12, pp. 11<J:~>, 1166). — The author used the Schmidt treatment for this 

 disease for l' years. Considerable trouble was experienced, however, from complica- 

 tions which appeared in the form of inflammation or diminution of the milk yield. 

 In about 50 per cent of the cases the yield of milk became so small as to render the 

 animal unprofitable. Much better results have been obtained from the use of pure 

 oxygen in treating milk fever. The udder is carefully disinfected before treatment. 

 Clinical notes are given on 4 cases in which the animals rapidly recovered. 



The influence of lactation on the resistance of the organism to pathogenic 

 bacteria, Cuakrin and Vitkv (<_'<>iiipt. Rend. Acad. Sei. [Paris], 139 (1004), No. 2,, pp. 

 2 !'.)-.. '2,1 ) . — As a rule the function of lactation has been considered as inducing a series 

 of changes which render the organism more susceptible to infection with disease. 



A considerable series of experiments were made on guinea pigs for the purpose of 

 testing the influence of lactation on infection. It was found that lactation causes a 

 number of physiological changes which, temporarily at least, reduce the resistant 

 power of the organism to pathogenic bacteria. These changes consist partly in a 

 variable degree of autointoxication and of increased sensibility toward toxins of 

 various sorts. 



QSsophagostorniasis, D. F. Luckey (Missouri State Bd. Agr. Mo. Bui., 4 (1904), 

 No.4,pp- 5-12, fig. 1). — During the past 2 years numerous reports have been received 



