896 EXPERIMENT STATION RECORD. 



tion of some raw meat durinji; a part of tlie time, the average cost of tlu- diet lii'ing 

 about 30 cents per day. 



Yeast and its household use, F. C. Harrison {Ontario Agr. Col. and Expt. 

 Farm Biil. US, pj). 16, figfi. 6) . — As a result of experiments made to determine the 

 rapidity of fermentation of yeast procured from a number of sources, it was found 

 that " there were three which gave a much more rapid fermentation than any of the 

 others, and which were considered to be equal. One of these was from a distillery, 

 one from a compressed yeast (sold for bread making and ordinarily produced at a 

 distillery), and the third from a home-grown yeast which had been started with a 

 compressed distillery yeast. The beer yeasts in several instances gave l^etter results 

 than yeasts sold specially for bread making. Home of the latter gave very poor 

 results indeed, showing that sufficient care had not been taken when starting the 

 growth of the yeast at the factory to obtain one which was well adapted to bread 

 making. The experiments show the superiority of distillery yeasts over brewery 

 yeasts for the fermentation of flour. They seem to act upon the starch of the flour 

 more energetically than do the beer yeasts. In experiments made on mixtures of 

 flour and water in fermentation tubes, the distillery yeasts always produced con- 

 siderably more gas than did the other kinds; they also produced the gas more 

 quickly." 



The general subjects of yeasts and their uses are discussed an<l suggestions are 

 given for the household preparation of yeast. The comparative merits of different 

 sorts of bread are also spoken of briefly. 



ANIMAL PRODUCTION. 



The principles of animal nutrition, H. P. Akmsby {New York: John Wiley & 

 Son>t, 1903, pp. VIJI-{-614) . — This volume, which in substance represents the author's 

 lectures before the Graduate Summer School of Agriculture at the Ohio State Univer- 

 sity in 1902, summarizes in systematic form the valuable information which has accu- 

 mulated regarding the principles of animal nutrition, especially from the standpoint 

 of energy relations and their bearing upon the nutrition of farm animals. The main 

 divisions of the volume deal with the income and expenditure of matter and of 

 energy. Under the former subject the author discusses food, metabolism, methods 

 of investigation, fasting metabolism, the relations of metabolism to food supply, and 

 the influence of muscular exertion upon metabolism. In the section devoted to 

 energy the subjects are force and energy, methods of investigation, the conservation 

 of energy in the animal body, food as a source of energy — metabolizable energy, 

 internal work, net available energy — maintenance, and the utilization of energy. 

 In every case the author has discussed in detail the results of experiments pub- 

 lished by numerous writers and sunmiarized them with especial reference to their 

 bearing upon the metaljolism of matter and energy. 



The most satisfactory terminology for use in discussions concerning the income and 

 outgo of energy is a matter on which oi>inions differ, and Professor Armsby has pro- 

 posed the term "metabolizable energy" for that fraction of the energy of the food 

 which can enter into the metabolism of energy in the l)ody. "Metabolizable energy, 

 then," he states, "may be briefly defined as potential energy of food minus potential 

 energy of excreta, including under excreta, of course, all the wastes of the body, 

 visible and invisible. The method is analogous to that of the determination of 

 digestibility. In both cases it is a calculation by difference, and the result shows 

 simply the maximum amount of matter or of energy put at the disposal f)f the 

 organism without affording any clue to the use made of it by the latter — that is, to 

 its availability in the more restricted sense." 



