ANIMAL PRODUCTION. 369 



G : N ratio 3.8 : 1. Body proteins of tlie other higher animals, includins man, 

 very probably yield nearly the same amounts of metabolic glucose as the dog 

 and rabbit. 



" The calculated yield of 45 per cent glucose, as a maximum from body pro- 

 tein, based on the urinary G:N ratio 2.8 : 1 in phlorizin and pancreas diabetes, 

 is incorrect." 



Animal calorimetry.— XII, The influence of the ingestion of fat, J. R. 

 MuELiN, G. LusK, and J. A. Riche {Jour. Biol. Chem., 22 {li)15), No. 1, pp. 

 15-29, figs. S).— The experiments reported in previous papers (E. S. R., 33, p. 755) 

 have been extended to include a study of the metabolism of laboratory animals 

 (dogs) after the ingestion of fat alone and combined with glucose and glyco- 

 coll. The experimental procedure was essentially the same as that de.scriljed in 

 the previous articles. The heat production of the dogs was observed after the 

 ingestion of 75 gm. of emulsified fat, after the ingestion of 75 gm. of fat followed 

 by 70 gm. of glucose, and after the ingestion of 50 gm. of glucose and 20 gm. of 

 glycocoll 4 hours after 75 gm. of emulsified fat had been eaten. The fat emul- 

 sion used consisted of 1 per cent lecithin, 37 per cent peanut oil, 37 per cent 

 lard oil, and 25 per cent water. 



These experiments showd that " the administration of fat causes a relative 

 increase in the metabolism of fat itself. . . . 



" The increase in heat production is derived from the increased oxidation of 

 incoming fat." 



The respiratory quotient obtained in the animals to which glucose had been 

 administered after the ingestion of fat showed that " with an ample influx of 

 both fat and glucose at the same time, both food substances are simultaneously 

 oxidized and with a large increase in the heat production." 



It was also found that " after giving 20 gm, of glycocoll +50 gm. of glucose 

 during the height of the absorption of 75 gm. of fat, the increase in metabolism 

 is nearly the sum of the increases brought about by giving each substance sepa- 

 rately." 



In summarizing the results of these experiments the authors state that the 

 influx of fat globules into the blood stream through the thoracic duct reaches 

 its maximum during the sixth hour after the ingestion of fat. 



" The heat production of the organism may gradually rise, reach its maximum 

 during the sixth hour, and may fall to the basal level 10 hours after fat has 

 been ingested. It appears that the ingestion of fat does not change the quantity 

 of heat produced from protein and glycogen, but that the increased metabolism 

 is at the expense of the fat ingested. 



" If glucose be ingested at the time of the highest fat metabolism, the heat 

 production undergoes a second increase by the same quota which glucose alone 

 would have increased metabolism. At this level of higher metabolism the 

 respiratory quotient is 0.93 or 0.94, instead of unity, which it would have been 

 if glucose had been given alone." 



ANIMAL PRODrCTION. 



The mechanism of Mendelian heredity, T. H. Mokgan, A. H. Stuetevant, 

 H. J. MuLLER, and C. B. Bkidges {New York: Henry Holt & Co., 1915, pp. 

 XIII+262, pi. 1, figs. 64). — The chapters included in this book are Mendelian 

 segregation and the chromosomes, types of Mendelian heredity, linkage, sex • 

 inheritance, the chromosomes as bearers of hereditary material, the correspond- 

 ence between the distribution of the chromosomes and of the genetic factors, 



13522°— No. 9—15 6 



