782 EXPEBIMEXT STATION RECORD. 



mittent fever. A ijosl-mortem examination nhowed lesions indicative of Texas 

 fever. Temperature charts of tliree animals are jtresented. 



"The iiinuunizatiou of susceptiblo cattle from the T'nited States by the 

 method of toTitrolliiiK' tick infestation has not proved complete or reliable, but 

 results in wliat apiiears to be a chronic form of the disease. In the Introduction 

 of cattle into Guam the j^reat importance of securing; immune stock is plainly 

 recosnized." 



Diseases of swine, S. S. IU;cklkv i MaryUuid tita. JUul. 185 {lUlJf), pp. 59- 

 g7). — j^ brief summarized account is given of the diseases of swine most com- 

 monly mot with in Maryland. 



Hog cholera, T>. L. T>EWis, W. P. Shxjleb, O. H. McElroy, and L. B. Ritteb 

 (Oklithotna ,Sta. Bill. lOIf (lOJJf), pp. 30, flg.'i. 10). — Following a general statement 

 relative to hog cholera in Oklahoma and a description of the disease and its 

 distribution, the findings on post-mortem, and methods of producing and using 

 antihog-cholera serum, some experimental data collecte<l during routine work 

 in this branch are reported. 



Examinations of the blood showetl that in unc()mj)licated cases of hog cholera 

 there is a general tendency toward a reduction of red and white blood cells 

 and in the amount of hemoglobin. In one case the erythrocytes were reduced 

 from 5,T40.(XX) to 2,000,000 per cubic millimeter in 12 days as a result of 

 inoculating virus and a reduction of the leucocytes from 25,000 to 7,000 per 

 cubic millimeter. In some observations on the changes produced in the blood 

 by hyperimmunizing with the slow or subcutaneous method and successive 

 bleedings from the tail at intervals of from 8 to 12 days, it was found that the 

 " introduction of the virus appears to lessen very materially the red cell 

 count, but does not affect the leucocytic count to the same extent. The amount 

 of blood taken at each bleeding was approxirnately 750 cc. (6 cc. per pound of 

 weight)." Neither the leucocytes nor the percentage of hemoglobin ai)pears to 

 be affected to a marked degree by the process. In studying the effect of the 

 intravenous method of inoculation the data show " that there is a reaction in 

 from one to four days after immunizing, the temperature rising from 1 to 5° F. 

 There does not appear to be any marked effect on the percentage of hemoglobin. 

 The white blood corpuscles are increased in each case after the injection of the 

 blood, and as a rule a slight rise in the number of red cells will be noted." 



Quinin hydrochlorate was studied as regards its influence on the course of 

 hog cholera. " So far as the four cases studied are concerned, quinin in the 

 amounts given failed to influence the course of the disease, but did api^ear to 

 have some effect on the period of incubation. The blood count in these cases 

 was variable, but the general tendency of all the hogs was to show a lower 

 count toward the termination of the disease. Temperatures were variable 

 and did not show any effect of the administration of .the quinin s<ilution. 

 Quinin hydrochlorate was administered hypodermically in 14.3-grain doses. 

 All of the pigs were killed as their physical condition indicated that death 

 would occur within a short time." A few cases showing the effect of intra- 

 venous injections of cold physiological salt solution •and a large amount of 

 vaccine in one case are also reported upon. 



" Experiments were conducteti in connection with the hog cholera serum 

 work to determine the time after hyperimmunizing before the blood from the 

 hyijered or treated hog ceases to be virulent to normal hogs. The test was 

 planned so that checks could be had on the virulence of blood used for hypering 

 and to keep the test pigs in pens free from any outside infection. . . . The 

 result of one of the tests shows that blood drawn 24 hours after hypering does 

 not contain virulent material; also that the blood drawn after four or five 

 days is not sufficiently potent as a vaccine to be relied upon to protect a hog 



