1919] VETERINARY MEDICINE. 179 



lbs., respectively. The average age at first parturition for the three groups 

 was LIT. 84.4, and 37.5 months, respectively. 



"It may be concluded from the foregoing that the most profitable age for first 

 calving among breeds maturing at or about the age of the Ayrshire lies beyond 

 the 80-month limit, and that then' is little to be gained bj permitting the 

 thirty-sixth month to pass by before first parturition." 



The Guernsey breed, C. L. Hill (Waterloo, Iowa: Fred L. Kimball Co., J917, 

 pp. .' f n, figs. 194)- — This volume is a condensed treatment of the history of the 

 Guernsey breed by a breeder who has long been identified with the American 

 Guernsey Cattle Club. The origin and development of the breed on the island 

 of Guernsey and its history in England are subjects of several chapters, but 

 most of the book deals with the breed in America, including notes on the earlier 

 importations, the first private and official tests, records made in public tests, 

 and performance in fhe show ring. The last and longest chapter in the book 

 deals with the families of Guernsey cows, of which about 25 are recognized. 



Milk supply and public health, Ella Guoenewold (Quart. Jour. Univ. N. 

 Dak., 8 (1918), No. 3, pp. 289-854, figs. S).— This is a summary of information 

 on bacteria In milk, infant mortality and impure milk, certified milk, pasteur- 

 ization and transportation of milk, and inspection of milk supply. 



Why liberal use of milk in the diet insures good health and long life. 

 J. V. Lyman (Agr. Student, 25 (1918), No. 2, pp. 77-81, figs. 2).— This is a brief 

 discussion of the value of milk and of the necessity of its liberal use in the 

 diet of both children and adults. 



VETERINARY MEDICINE. 



The study of problems of immunity by the tissue culture method. — I, II 

 {Jour. Immunol., 3 (1918), No. 3, pp. 219-2J t 6, figs. 4). — Two papers are pre- 

 sented. 



I. A study of the cells and blood plasma of animals which are naturally re- 

 sistant and others which are susceptible to diphtheria and tetanus toxins, by 

 Y. Suzuki (pp. 233-246). — In this paper a method is described for determining 

 the presence and studying the properties of the protective substances in animals 

 that are naturally Immune and in those that are susceptible to bacterial and 

 other toxins. The method consists in studying the growth of tissue cells in their 

 own and in foreign plasma with and without the addition of suitable toxins 

 The tissues were prepared from the heart muscle and ovary of chickens and 

 rats, those being chosen since chickens have a natural Immunity for tetanus 

 and rats for diphtheria. The experiments reported tend to prove that this 

 natural immunity is due to two factors — a special resistance of at least certain 

 of the cells of these animals and the existence of neutralizing substances in 

 their plasma. The plasma protects not only the cells of these animals against 

 lethal doses of toxin but also the cells of susceptible animals. 



II. The tissue culture as a means for quantitatively estimating toxin and 

 antitoxin and determining the distribution of antitoxin in passively immunized 

 animals, by M. T. Burrows and Y. Suzuki (pp. 219-232). — In tins paper are 

 described further experiments outlined for the purpose of studying more care- 

 fully fhe general distribution and action of antitoxic substances. The tissue 

 cells of young chickens and chick embryos were studied. 



The sensitiveness of the cells of chick embryos to diphtheria toxin was found 

 to vary inversely with the age of the embryos. As a considerable concentration 

 of diphtheria antitoxin did not affect the growth of the cells, it was found 

 possible to test the effect of various dilutions of diphtheria toxin on the growth 



