192 EXPERIMENT STATION RECORD. [Vol. 41 



agglutination was obtained with any quantity of serum not exceeding 0.01 cc. 

 The reliability of the test as based on this standard was as follows : 



All but two of the animals which had shown clinical signs of tlie disease 

 gave a positive reaction. The organism was found only in animals giving a 

 positive test. With one exception, all animals experimentally infected with 

 cultures of Bacillus abortus subsequently gave positive tests. In all agglutina- 

 tion tests made of guinea pigs which had become infected by inoculation 

 with cow's milk and from which B. abortus had been cultured, a positive 

 reaction was obtained. Conversely, guinea pigs which failed to become in- 

 fected did not give a positive agglutination test. 



A detailed history illustrated by charts is given of the course of abortion 

 disease in the herd under investigation, with interpretation of results. In 

 conclusion, the author states that in the light of recent knowledge the problem 

 of abortion disease may be summarized as follows : 



When a nonpregnant animal becomes infected, the orgauism gains a lodg- 

 ment in the mammary gland. In an infected pregnant animal, the organism is 

 present in both mammary gland and uterus. After abortion the uterus quickly be- 

 comes free from abortion bacilli, but infection persists in the mammary gland 

 and provides the source of the abortion bacilli present in the uterus at a future 

 pregnancy. 



A certain percentage (10 per cent of the cases reported) become infected 

 only in the uterus and may recover from that infection. Bulls may act as 

 mechanical carriers of infection, or may become infected in the testes or 

 epididymis and eliminate organisms along with the seminal fluid. Animals 

 may give a negative agglutination test till a few weeks before abortion. These 

 conclusions are in agreement with those of Schroeder and Cotton previously 

 noted (E. S. R., 36, p. 881). 



Contagious abortion of cattle: A bibliography {Vet Rev., 3 (1919), No. 2, pp. 

 137-152).. — This bibliography of 225 titles covers the literature on contagious 

 abortion of cattle since 1895, with a few references to earlier literature. 



Treatment of contagious lymphangitis in horses by pyotherapy, Belin 

 (Bui. Soc. Cent. MM. Vet., 95 (1919), No. ^, pp. 73-93).— This is a report of 

 observations of 114 cases of cryptococcic (epizootic) and 247 cases of bacillary 

 (ulcerous) lymphangitis treated by pyotherapy, which strengthens the author's 

 opinion that pyotherapy is the only rational method for the treatment of con- 

 tagious lymphangitis. A new method of sterilizing the pus for the preparation 

 of the pyovaccine is recommended, in which a solution of 1 part idoin and 4 

 parts potassium iodid in 1,000 cc. of distilled water is employed in place of 

 the ether previously recommended (B. S. R., 38, p. 587). 



The poultryman's parasite problem, W. C. Thompson (New Jersey Stas., 

 Hints to Poultrymen, 7 (1919), No. 8, pp. J/). — A brief account is given of the 

 common ectoparasites of poultry and means for their control. 



RURAL ECONOMICS. 



How these farmers succeeded, edited by J. R. McMahon (New York: Henry 

 Bolt <C- Co., 1919, pp. VI 1 1 +261, pis. 50).— This book is a collection of articles 

 published in a "Best Parmer" series in the Country Gentleman, describing 16 

 successful farms in the United States. 



Farm products and cost accounting, H, J. Davenpobt (Jour. Polit. Econ., 

 27 (1919), No. 5, pp. 354-361).— The argument prompting this analysis is that 

 the high price fixed for wheat becomes a contribution to the cost of the alter- 

 native products of farming and limits the supply of them. This analysis, 



