684 EXPERIMENT STATION RECORD. [Vol.41 



in bulls appears to be more strongly indicated by relatively marked than by 

 slight reactions to the agglutination test for this disease." 



Stomach worm disease in cattle and sheep, W. H. Dalbymple (La. Agr. Col., 

 Ext. Div. Circ. SI (1919), pp. 8, figs. 6). — A brief summary of information. 



Less cholera, more hogs, O. B. Hess (U. S. Dept. Agr. Yearbook 1918, pp. 

 191-194, pis. 2). — A popular discussion, in which attention is called to the man- 

 ner in which hog cholera is now being combated and the results obtained. 



Effects of heat on trichinae, B. H. Ransom and B. Schwabtz (Jour. Agr. Re- 

 search [U. S.], n (1919), No. 5, pp. 201-221).— This is a report of work com- 

 menced and carried on in 1913, 1914, and 1915 by the senior author and taken 

 up since the latter part of 1915 by the junior author, both of tlie Bureau of 

 Animal Industry of the U. S. Department of Agriculture. 



The authors find that the vitality of the larvae of Trichinella spiralis is 

 quickly destroyed by exposure of the parasites to 55° C. (131° F.), gradually 

 attained, the result apparently of irreversible coagulation changes in the proto- 

 plasm. 



" Trichina larvae exposed to temperatures slightly below 55° for short periods 

 of time may recover from this exposure ; but they die if exposed for longer 

 periods, recovery or death depending apparently upon whether or not beginning 

 coagulation of the protoplasm has proceeded beyond a stage from which a return 

 to normal may occur. Exposed to temperatures in the neighborhood of 50°, 

 trichina larvae die if the application of heat is sufficiently long continued, appar- 

 ently as a result of exhaustion following excessive activity to which they are 

 stimulated by the heat. 



" The longevity of trichina larvae freed from their cysts by artificial digestion 

 and kept at temperatures ranging between limits at which they became quies- 

 cent from the effects of heat and cold, respectively, varies inversely with the 

 temperature. 



" Methods of destroying trichinae by heating at temperatures below the thermal 

 death point, which may be utilized in connection with the preparation of certain 

 kinds of cured pork products, appear not to be applicable in the case of fresh 

 pork. 



" Upon the basis of the results of experiments recorded in this paper, the 

 Bureau of Animal Industry has selected a temperature of 137° F. (58.33° O.) 

 as the minimum temperature to which pork and products containing pork are 

 required to be heated when cooked in establishments operating under Federal 

 meat inspection. This temperature is several degrees above the thermal death 

 point of trichina larvae, thus providing a certain margin of safety." 



The literature is reviewed and a list of 14 references is appended. 



The cause of abortion in mares, C. Murray (Jour. Infect. Diseases, 25 (1919), 

 No. Jf, pp. S^lS/fS). — " From an outbreak of abortion in Iowa there was isolated 

 an organism of the paratyphoid-euteritidis group, which in cultural and morpho- 

 logic characters and in serologic reactions is apparently the same as the organ- 

 ism studied by Good, Meyer, and others [E. S. R., 27, p. 580; 30, p. 586], and 

 variously named by them B. abortivo-equiivus, B. abortus equi, etc. The dry, 

 brittle, membranous growth on slanted agar which was observed by these inves- 

 tigators was present in the cultures isolated in this outbreak, and this peculiarity 

 Is of great value in identification of the organism. With this organism 

 abortion was produced in the rabbit, guinea pig, sow, and mare by intraperi- 

 toneal or intravenous injection of minute doses in 2, 6, 2, and 11 days, re- 

 spectively. Feeding and intravaginal introduction of the organism did not 

 result in abortion in any animals thus treated. 



