ANIMAL PRODUCTION. 471 



met with in either physical or chemical operations and heretofore never in 

 physiological chemical operations. Indeed, the apparatus has proved as accu- 

 rate as any chemical process ordinarily used in a laboratory, and it can 

 accordingly be characterized, both calorimetrically and chemically, as an 

 instrument of precision." 



For earlier work, see previous notes (E. S. R., 17, p. 1008; 18, p. 1151). 



A comparison of the direct and indirect determination of oxygen consumed 

 by man, F, G. Benedict (Amer. Jour. Physiol., 26 {1910), No. 1, pp. 15-25). — 

 The direct determination of oxygen in experiments with the respiration calorim- 

 eter in comparison with calculated values is discussed by the author. 



From the results of check tests in which alcohol was burned in the respira- 

 tion chamber, and more particularly from the results of determinations of 

 oxygen by both the direct and the indirect methods, the conclusion is reached 

 that the direct determination is accurate, " and that experiments on man can 

 be made in which the direct determination of oxygen is fully substantiated by 

 the indirect determintion. Personal experience would indicate that the errors 

 involved in the indirect determination of oxygen are such as to preclude its use 

 under conditions that ordinarily obtain in even the most perfect forms of res- 

 piration apparatus, and that accurate determinations of the oxygen consump- 

 tion of man are practicable only by means of the direct method. 



" While a number of years ago the close agreement between the direct and 

 indirect determinations of oxygen shown in these experiments would have been 

 of value as an indication that no demonstrable quantities of nitrogen were 

 eliminated as such from the body of man, in the light of the recent brilliant 

 research of Krogh [E. S. R., 18, p. 760], it is unnecessary to more than point 

 out the significance of this agreement in experiments on man as substantiating 

 the results of Krogh when experimenting on small animals." 



ANIMAL PRODUCTION. 



Recent science in plant and animal breeding, W. M. Hays (Live Stock Jour. 

 [Chicago], 51 (1910). Xo. 25. pp. 353-355, 358, 359, figs. 15).— An address before 

 the American Seed Trade Association, June 22, 1910, in which the author points 

 out the value of scientific investigations in the breeding of plants and animals. 



The struggle for existence and breeding experience, Arnim-Schlagenthin 

 (Der Kampf urns Dasein und ziichterische Erfahriing. Berlin, 1909, pp. Z+ 

 lOS). — A discussion of Mendel's law, mutation, and other factors concerned in 

 the evolution of plants, animals, and man from the standpoint of one who 

 does not believe in the inheritance of acquired characters. The view is 

 expressed that the factor " struggle for existence " has little or no value in 

 the evolution of wild or domesticated species or in the progress of nations. 



The controversy on the significance of the nucleus in inheritance and de- 

 velopment, O. Hebtwig (Der Kampf um KernfragOiv der Entwickluiigs- und 

 Vererhungslchre. Jena, 1909, pp. IV+122; rev. in Nature [London], 83 (1910), 

 No. 2119, p. ff26). — The author presents evidence to strengthen the theory that 

 the basis of inheritance is localized In nuclear substance and in refutation of 

 the arguments which have been advanced agninst the theory. 



The catalytic activity of the developing hen's egg, M. C. Winternitz and 

 W. B. Rogers (Jour. Expt. Med., 12 (1910), No. 1, pp. 12-18, chart 7).— Two 

 series of fresh eggs were procured. Some of the eggs were tested immediately 

 for catalytic activity, others were left unincubated for varying periods up to 

 2i months, and the remainder were incubated at approximately 37° C. test 

 for catalytic activity being made at intervals of 2-x hours. The results with 

 the 2 series were practically the same. 



59393°— No. 5—10 6 



