972 EXPERIMENT STATION RECORD. 



" While the chlorophyll reduces the heat of couibustion of the ether extract, 

 there are compeusatiug factors ; its presence in the fodder is a desirable char- 

 acteristic, for the color of the fodder is due to chlorophyll and is an index of 

 quality. Feeders .iustly give preference to well-cured fodders of good color." 



The digestibility of rye feed meal, O. Kellner et al. {Landic. Vers. Stat.. 

 6') {19(11), So. .5-6. pp. .',IU)--'il'(l). — In digestion experiments with sheep it was 

 found that rye feed meal on an average had the following coefficients of digesti- 

 bility : Dry matter, 92.7 : protein. T.j.!), and nitrogen-free extract, 9G.8 per cent. 



The facility of digestion of foods a factor in feeding, C. L. Beach (Coh- 

 nectiviit Storm tstd. Bui. If.i. pp. ^J). — A series of tests is reported in which corn 

 meal and mixed hay in turn were fed as a maintenance ration to '2 dry. farrow 

 cows. The results of tests with milch cows, pigs, and calves are also quoted 

 and discussed for purposes of comparison. 



On an average 6.25 lbs. of corn meal containing 4..j lbs. digestible nutrients 

 was reijuired for maintenance by the farrow cows as conq)ared with 1.3.15 lbs. 

 of hay containing 7.1 lbs. of digestible nutrients; that is. on an average 57 per 

 cent more digestible nutrients was required for maintenance when derived from 

 hay than from corn meal. " Less digestible nutrients from corn meal, therefore, 

 were required for maintenance than from hay, because less energy of the feed 

 was used in the work of digestion and assimilation." "An increase in the proiwr- 

 tion of grain to roughage in a ration for milch cows [in tests which were quoted] 

 tends to facilitate digestion, and is followed by increased production." 



A similar explanation will account for the more rapid gain in the case of the 

 pigs and calves fed the more easily digestible rations in the tests summarized. 

 In general, according to the author, "the value of a feed dei)ends upon its com- 

 position, digestibility, and ease or facility of digestion. The first two factox-s 

 are considered in the formulation of rations. The third factor has only recently 

 been recognized, and little definite knowledge in regard to it is at hand. In a 

 general way it is recognized that milk is more easily digested than meal, con- 

 centrates than roughage, early than late cut h.iy. silage than corn stover, out 

 than rye straw. A pound of digestible matter, therefore, should be more 

 valuable in the former than in the latter." 



Investigations in the use of the bomb calorimeter, J. A. Fries ( U. S. Dcpt. 

 Ayr., Bur. Anhii. Indus. Bill. 9'/. pp. 39). — The results of investigations like 

 those cai'ried on with tlie respiration calorimeter at the Pennsylvania Experi- 

 ment Station in cooperation with the Bureau of Animal Industry depend for 

 their value in large measure upon accurate determinations of the heats of 

 combustion of feed, lU'lne. and feces. Critical studies were therefore under- 

 taken of the determination of such values and the factors which affect the 

 accuracy of results and related (luestions. 



The bomb calorimet(>r used is briefiy described and the methods of operating 

 it are outlined. Among the factors affecting accuracy of results which were 

 investigated were the quality of the oxygen, the formation of nitric acid in 

 the bomb during combustion, the oxidation of combined nitrogen to nitric 

 acid, and incomplete combustion. 



The experimental and analytical data reported led to the following con- 

 clusions: "There are many jiossibilities for error in the work with the bomb 

 calorinieter. Undoubtedly many investigators in the past have worked with 

 impure oxygen and never questioned its purity. In the light of our present 

 experience it is questionable whether Stohmanu himself, by the use of a heated 

 copper tube, could have I'emoved the last traces of combustible gases from 

 his oxygen. The disappearance of nitric acid formed and its relation to the 

 ash has not been taken into consideration, and It is only within a couple of 



