174 EXPERIMENT STATION RBCOED. 



On the metabolism experiment as a statistical problem, H. L. Rietz and 

 H. H. Mitchell (Jour. Biol. Chem., 8 {1910), No. .',, pi). 297-326).— The authors 

 discuss the iuterpretation from a mathematical standpoint of the results of 

 physiological experimenting, particularly in component results such as a 

 standard deviation, by the application of the so-called " probable error " ob- 

 tained from Gauss' exponential equation. 



" Not only is the probable error a convenient criterion for the evaluation of 

 experimental results in metabolism, but it is a necessary criterion that must, 

 in many cases, be applied before definite, especially quantitative or general con- 

 clusions, may legitimately be deduced. 



" It follows, therefore, that experiments in this field should be so planned as 

 to conform the most strictly with the requirements for the application of the 

 law of probability and to yield the most valuable results as judged by this 

 method. 



"Under such conditions, we mny confidently expect that the laws of proba- 

 bility, together with the various mathematical methods for reducing statistical 

 data in common use among statisticians, will render a tremendous service to 

 physiology and physiological chemistry as they have to such problems of general 

 biology as heredity and evolution. Further, we do not hesitate to predict that, 

 by the use of such methods, a greater degi-ee of exactness and precision and, 

 conversely, a narrower field for the exercise of unaided judgment or biased 

 opinion in the interpretation of experimental data will result, fully repaying 

 the extra labor and care involved in conforming to the requirements of these 

 methods." 



A respiration apparatus for the study of isolated organs and for use -with 

 small animals, O. Cohnheim {Ztschr. Physiol. Cliem., 69 {1910), No. 2, pp. 

 89-95). — The apparatus, which is briefly described, is of the closed-circuit type 

 and constructed on the principle of the Atwater-Benedict apparatus. The 

 method of operation and sources of error are considered. 



ANIMAL PRODUCTION. 



The kudzu vine as a forage crop {Rural Xfw Yorker, 69 {1910), No. .'i068, p. 

 963, figs. 3). — The experience is reported of a farmer in Florida who has grown 

 the kudzu vine {Pucraria tliunbergiana) as a forage crop and thinks it su- 

 perior to cowpeas or velvet bean for hay or pasture. Four different cuttings 

 were made as follows: May 1, at the rate of 3.63 tons; June 12. 2 tons; July 

 30, 2.89 tons ; and September IS. 2.43 tons of dried hay per acre, making a total 

 of 10.95 tons in one season. Analysis of the first cutting showed that it con- 

 tained 17.6 i^er cent protein and 34.33 per cent carbohydrates; of the third 

 cutting, 14.8 per cent protein and 35.05 per cent carbohydrates. 



Observations on the use of cactus for feeding animals, E. Baillaud {Jour. 

 Agr. Trop., 10 {1910), Xo. Ill, pp. 257-262). — A summary of feeding tests, in 

 which cactus constituted a part of the ration. 



Alfalfa hay for hogs, .J. M. Evvard {Nat. Swine Mag., 5 {1910), No. 1, pp. 

 5-7, figs. 2). — A popular summary of information on the value of alfalfa hay 

 for swine feeding. 



Notices of judgment ( V. 8. Dcpt. Agr., Notices of Judgment 5S2, 60S, p. I 

 each). — These relate to the adulteration and misbranding of oats and the 

 misbranding of alfalfa meal. 



Biological observations on the growth of animals at pasture, Falke {Biolo- 

 gische Beohachtungcn iiher das Wachstum dcr Weidetiere. Hanover, 1910, pp. 

 28; rev. in Zenthl. AUg. n. E.vpt. Biol., 1 {1910), No. 7-8, p. .27'i).— The increase 

 in height of cattle at pasture was often more rapid than the gain in weight. 



