ANIMAL PRODUCTION. 167 



one would have to take into accouut extremely high temperatures if a thermo- 

 dynamical explanation were offered. 



The chief work reaction which causes contraction depends upon the formation 

 of lactic acid. As yet the origin of the lactic acid is not known. Probably it 

 does not come directly from glycogen or from dexti'ose. When muscle is stim- 

 ulated and fatigued, the lactic acid disappears, oxygen being taken up and 

 carbon dioxid given off, not, however, by means of simple combustion but 

 through the regeneration of the lactic-acid-yielding substances coupled with an 

 oxidative process. Muscular contraction is apparently brought about by a 

 swelling which is itself brought about by the presence of the acid. The laws 

 of the increased volume phenomena are the same as those for the dilution of 

 concentrated solutions. In this case, as in the case of the muscle, practically 

 all the energy changes can be noted as work. 



A discussion follows the paper. 



Protozoan protoplasm, as an indicator of pathological changes. — III, In 

 fatigue, F. P. Underbill and L. L. Woodrvff (Jour. Biol. Chem., 11 (1914), 

 No. 1, pp. 9-12). — From the experimental data which they report, the authors 

 believe that " it is justifiable to conclude that the character of the chemical 

 changes occurring in fatigued muscle must differ only slightly from the normal." 



ANIMAL PRODUCTION. 



Live stock on farms and elsewhere (Thirteenth Census U. 8., 5 {1910), pp. 

 327-472, pis. 7, figs. 10). — The total value of all live stock on farms in the 

 United States on April 15. 1910, was $4,925,174,000. Of this total, domestic 

 animals represented 9G.6 per cent and poultry most of the remainder. 



During the decade 1900-1910 the value of live stock on farms increased 60.1 

 per cent. The increase was shared by every geographic division. The largest 

 absolute increases were in the West North Central and the East North Central 

 divisions, though with respect to percentages of increase the Pacific division 

 ranked highest, closely followed by the South Atlantic division. The highest 

 percentage of increase was in the West. The North reported in 1910 a little 

 over three-fifths of the total value of all live stock on farms in the United 

 States, the South somewhat over one-fourth, and the West about one-eighth. 

 The average value of live stock per farm for the United States as a whole was 

 $774 in 1910, for the North $1,029. for the South $428, and for the West $1,673. 



In value of domestic animals Iowa outranked all other States in 1910, fol- 

 lowed in order by Texas, Illinois, Missouri, Kansas, and Nebraska, each report- 

 ing over $200,000,000. In value of poultry Iowa also ranked first, followed by 

 Missouri and Illinois, each with over $10,000,000. 



Data are given in detail for cattle, horses, mules, swine, sheep and goats, 

 poultry, and bees on farms, and of domestic animals not on farms. 



Live stock products and domestic animals sold or slaughtered on farms 

 (Thirteenth Census U. 8., 5 (1910), pp. 473-529, figs. 3). — There were on April 

 15, 1910, 598,047 farms, or 9.4 per cent of all farms in the United States, with 

 sheep of shearing age, the number of such sheep being 39,644,000. 



The value of the wool clipped was $45,670,000 in 1899 and $65,472,000 in 1909. 

 The average value per fleece increased from $1.04 to $1.55, and the average value 

 per pound from 17 to 23 cts. Of the three principal wool-producing divisions, 

 the East, North Central, and Pacific each reported a smaller proportion of the 

 total wool clip in 1909 than in 1899, and the Mountain division a larger pro- 

 portion. The most important State in the production of wool was Wyoming, 

 with Montana, New Mexico, Ohio, California, Idaho, Oregon, and Texas rank- 

 ing in order named. 



