VKTEKINAKY SCIENCE AND TKACTICE. 897 



after a jieriod of 4 week?, or rarely pnuluoed any effect whatever. It \va.s s-liown- 

 that artificial cultures of the ho<r-cholera bacillus may become attenuated after several 

 months fjrowth on nutrient media in the laboratory. With regard to the prolilem 

 of possible recurrence of the disease in hogs whicli have recovered from one attack, 

 it is suggested that tests should be made in exposing recovered animals to infection 

 from fresh sources. No such tests, however, have thus far been made. It was 

 found impossible to produce the disease artificially in a hog which had recovered 

 from an attack, and the evidence is in favor of the belief that one attack produces 

 immunity. Hog cholera and swine plague are usually combined in the same attack. 

 In bacteriological studies made by the author no cases were found in which it was 

 possible to assert that hog cholera was not combined with swine plague, but in some 

 cases the organism of swine plague was found unassociated with that of hog cholera. 

 In several cases the bacillus of swine plague was found where the hog cholera l>aciliug 

 could not be demonstrated. It is possible, however, that one disease may partly 

 run its coui-se, but later be obscured by the predominance of the other associated dis- 

 ease. The author consi<lers it unsafe, therefore, to assert that swine plague occurs in 

 Arkansas as an independent disease, spreading by contagion like cholera. 



Notes are given on the occurrence and injurious effects of lung worms, Ascarides, 

 and Echinorhynchi. Attention is called to the difficulties of diagnosing hog dis- 

 eases from the symptoms on account of the fact that such great variations in symp- 

 toms are observed and on account of the similarity of symptoms in different diseases. 

 With regard to the treatment of hog diseases the author found all direct remedies 

 unsatisfactory. Even in treatment of hogs for worms the use of vermicides, such 

 as naphthaline, santonine, and various purgatives, were not effective. The chief 

 effort of hog raisers should be in the line of prevention of hog diseases. The appli- 

 cation of the vaccine method in the control of infectious hog diseases has been tried 

 and favorably reported upon by this Department. With the author, however, this 

 method yielded no results whatever. It was also found that the vaccine w-hich pro- 

 tected against hog cholera had no effect against swine plague. A double vaccine w^as 

 therefore introduced which fulfilled all requirements of a vaccine in tests on labora- 

 tory animals. No opportunity, however, has been had for proper testing of the 

 matter in natural ontbreaks of hog cholera. 



The influence of cold on the development of pneumonia of the horse, J, 

 BouRGES {Rec. Mid. TV/., Paris, S. scr., 8 (1901), Ko. 26, pp. 386-340). — Observations 

 on the prevalence of pneumonia in horses in various countries were made for the 

 purpose of determining the influence of cold on the etiology of pneumonia. As a 

 result of observations on 2,850 horses and mules it is concluded that cold has no 

 effect on thoracic diseases. The prevalence of long periods of severe cold mav 

 weaken the animal to some extent, provided a corresponding increase in fodder is 

 not given to the animals. The practice of protecting horses to too great extent 

 against cold in winter is condemned. In order to secure artificial heat it is fre- 

 quently necessary to maintain the animals in quarters which are not as well venti- 

 late«l as they would be if less attention were given to the temperature. 



Report on the surra disease of horses, Schii-lixg {Ccntbl. Bald. u. J'ar., I. Abt.,. 

 30 {1901), No. 15, pp. 545-551). — The author gives a detailed description of the symp- 

 toms of this disease in a horse suffering from a natural infection. A purulent dis- 

 charge was noted on the eyelids and in the nasal cavity, and an (edematous swelling 

 extended from between the forelegs backwards for some distance on the inferior sur- 

 face of the body. The animal had a ravenous appetite until shortly before death. 

 The hemoglobin content of the blood was determined at from 25 to 30 per I'ent; body 

 temperature varied between 38.2 and 40° C. Two other cases were observed with 

 slightly different symptoms. Inoculation experiments were made on hoi-ses, an ass, 

 cattle, goats, hogs, and dogs. Hogs were refractory to the disease, but the other 

 animals became infected. Trypanosoma was found in large numbers and in an active 



