574 EXPERIMENT STATION RECORD. [Vol.43 



Studies relating to calcium metabolism, W. P. Wheeler {New York State 

 Sta. Bui. ji68 {1919), pp. 3-^S). — The author reports seven series of experi- 

 ments with chickens and clucks conducted at intervals over a term of years, 

 one series dating back to 1S97. The birds employed in the respective series were 

 young hens, chicks, laying liens, young ducks, ducklings, mature nonlaying 

 ducks, and laying ducks. The basal rations fed to all the birds were low in 

 calcium, tht; feeds being selected from the following materials: Cracked corn, 

 corn meal, corn gluten meal, starch, rice, rice flour, wheat flour, wheat gluten, 

 apples (without seeds), beef fat, bone-free meat scrap, blood meal, gelatin, and 

 common salt. During part of the tests with mature hens the yolks and whites 

 of eggs and sour milk whey were also fed. White quartz glass sand covered 

 the floor, and rain water was provided for drinking purposes. In addition to 

 the basal ration the three lots in each series received, respectively, magnesium, 

 strontium, and calcium carbonate, and in some cases also the corresponding 

 phosphates. Usually a lot consisted of six birds. They were killed at intervals 

 after several weeks to a year's feeding. Tables present the skeletal weights 

 of the slaughtered birds and mineral analyses of the axial and appendicular 

 skeletons and the shells of such eggs as were laid. 



No instance was found where magnesium served to any significant extent in 

 place of calcium to form egg shells directly or to replace the calcium withdrawn 

 from the skeleton for egg production. Strontium, on the other hand, although 

 normally not a constituent of the body or of ordinary feeds, did serve in place 

 of calcium in egg shells and bones. 



" Whenever rations deficient in calcium but carrying abundant supplies of 

 magnesium were fed to the common fowl and the duck, there soon followed a 

 noticeable shortage of calcium and of total mineral matter in the bones. With 

 mature birds whenever calcium was withdrawn from the skeleton it was usually 

 taken in larger proportion from the softer bones [axial skeleton], 



" When strontium salts were fed with low calcium rations for several weeks 

 or months to mature fowls, these birds always had heavier bones with more 

 mineral matter in them than did similar birds fed corresponding calcium or 

 magnesium salts. Where strontium replaced calcium in tlie bones of mature 

 birds, the ratio of replacement in every instance was higher in the .softer 

 bones." In some cases after prolonged strontium feeding more strontium than 

 calcium was found in the feathers. 



Of the two species, the common fowl showed the greater tolerance for stron- 

 tium and the duck a greater tolerance for magnesium. Ducks fed strontium 

 were noticeably deficient in body fat. More eggs were secured from hens fed 

 strontium than from those fed magnesium, while only very few eggs were laid 

 by strontium-fed ducks. Scai-city of calcium reduced egg laying markedly in 

 both the fowl and the ducii. 



Somethiiig about calcium in the body, W. P. Wheelek {New York State 

 Sta. Bui. Jf68, pop. ccl. {1919), pp. 3-11). — A popular edition of the above, em- 

 phasizing particularly the applications to human and animal nutrition. 



Capons V. cockerels. — A comparison of their rate of growth and feed 

 consumption, R. H. Waite {Maryland Sta. Bui. 235 {1920), pp. 119-132, figs. 

 9). — This bulletin reports the growth and feeding records of two lots of 21 

 White Plymouth Rock cockerels hatched March 28, 1919, from the age of 

 two months, when one lot were caponized, until the following Febi'uary, when 

 both were marketed. During the growing period tlie birds were given corn 

 and wheat and a dry mash of bran, middlings, and beef scrap (10: 10:3) plus 

 bone meal and salt. During a 3-week fattening period, begun January 17, 

 yellow corn and a wet mash of cornmeal, middlings, beef scrap, and alfalfa 

 meal (10:5:2:3), and salt were offered. 



