ANIMAL PRODUCTION. 273 



previously reported, " emphasizes the probability that readily saponifiable fatty 

 acid esters do uot escape saponification under the favorable conditions in the 

 normal intestine (excess of lipase, rapid removal of the products). Whether 

 fatty substances of any kind may pass into the chyle unchanged remains to be 

 proven." 



The chemical analysis of the ash of smooth muscle, E. B. Meigs and L. A. 

 Ryan {Jour. Biol. Chem., 11 {1912), No. J,, pp. 401~Jtl4). — Experiments are 

 reported and data summarized. According to the authors, the facts at present 

 known point to the following conclusions in regard to smooth muscle: 



" The fibers of this tissue are not surrounded by semii>ernieable membranes. 



" ISIost of the water of the smooth muscle fibers is held by the colloids of the 

 living tissue as organic water. 



" Most of the potassium, phosphorus, sulphur, and magnesium, which appear 

 in the ash of smooth muscle, are present in the living tissue in a nondiffusible 

 form." 



Metabolism during mental work, A. Lehmann (Umscliau, 16. {1912), No. 

 19, pp. 390, 391). — A brief summary of a paper presented at the Congress of 

 Experimental Psychology in Berlin. The mental work in the experiments con- 

 sisted in adding simple numbers or in committing to memory syllables arranged 

 without reference to meaning. 



The author concludes that under controlled conditions such mental work 

 caused an increase of carbon dioxid excreted which is directly comparable with 

 that noted in the case of physical work. The increased carbon dioxid production 

 was proportional to the severity of the mental work as measured by attention. 



A new ice chest, C Zelmanowitz {Biochcm. Ztschr., 39 {1912). No. 1-2, 

 pp. 151-15^1, fig. 1). — An ice chest designed for laboratory use is described in 

 which a current of air is driven into the ice chamber and kept in continuous 

 circulation by means of a small electric motor. The front of the ice box con- 

 tains a number of small doors, the object being to lessen the rise of tempera- 

 ture when articles are placed in it or removed. Even when due allowance is 

 made for the cost of the motor and power, the ice chest has been found more 

 economical than one cooled with ice in the usual way, according to the author. 



[The ideas embodied in the construction of this ice chest might prove useful 

 in ice chests for institution use or for some similar purpose.] 



ANIMAL PRODUCTION. 



The vitality of reproductive cells, L. L. Lewis {Oklahoma Sta. Bui. 96, 

 pp. 3~.'f7, figs. 7). — This contains a description of the reproductive glands of 

 horses, cattle, swine, and mules, and a report of experimental work on the 

 vitality of spermatozoa and ova, being a continuation of earlier work (see 

 page 274). 



Measurements of the speim cells from horses, catlte, and swine are given, 

 showing that there was but little variation in size for different individuals of 

 the same species. In a number of experiments in keeping semen of stallions 

 at temperatures from 12 to 52° C, the high temperatures were found to be 

 quickly fatal to the sperm cells. Keeping the semen in rubber and pig bladder, 

 or adding water or other materials, reduced the vitality. Semen-like material 

 from male mules contained no sperm cells. 



" Under experimental conditions the vitality of the sperm cells from the boar 

 continues approximately 15 to 25 hours after the semen is collected. The 

 length of time depending upon the temperature at which the semen is kept, 

 and the vigor and physical condition of the animal used in the experiment. 

 Temperature has much the same effect on the vitality of the semen from the 



