ANIMAL PRODUCTION. 267 



reptiles and fishes it is urea and nric acid, in many invertebrates it is uric 

 acid. In leucocytes, as invertein-ates, tlie end product of metabolism is most 

 probably uric acid. We are therefore inclined to conclude that the uric acid 

 in the urine is an expression of their metabolism. . . . 



" Further work will be necessary before the view here put forward can be 

 regarded as established, but our results certainly throw considerable doubt 

 on the prevalent opinion that the purins of the food and of the tissues are the 

 sole source of the uric acid in the urine." 



Comparative physiolog-y of purin metabolism, PI. G. Wells {Trans. Chi- 

 cago Path. *Soc., 7 (1909), No. 8, pi). 2////-J//8; Jour. Amer. Med. Assoc, 53 

 (1909), No. 21, p. 17J/1). — According to the investigations summarized, "the 

 invertebrates are able to convert adenin into hypoxanthin and guanin into 

 xanthin, showing the presence of the enzyms, adenase, and guanase, but the 

 metabolism proceeds no farther. Passing upward in the scale of animal life 

 to the birds and reptiles we find that nitrogen is excreted chiefly in the form 

 of uric acid. Mammals form uric acid only from the purins and have the 

 power of destroying some of the uric acid formed. The enzyms that destroy 

 uric acid seem to be the last formed in development and are possessed by vari- 

 ous mammals in varying degrees and in the same animal often show an uneven 

 distribution in the various organs of the body. This uricolytic power is rela- 

 tively weak in man." The paper is followed by a discussion. 



The effect of work on the creatin content of muscle, T. G. Brown and E. P. 

 Cathcabt (Bio-Chem. Jour., Jf {1909), No. 9, pp. .'120-426). — The general result 

 of the series of experiments reported, according to the authors, is that, "with 

 the circulation intact, stimulation of the muscles brings about a constant, 

 although small, decrease in the amount of total creatinin (i. e., creatin -f crea- 

 tinin) extracted from the stimulated muscle." The experiments were made 

 with small animals. 



The distribution of fat, chlorids, phosphates, potassium, and iron in 

 striated muscle, Maud L. Menten {Univ. Toronto Studies, Pliysiol. 8er., 

 1908-9, No. 7, pp. 21, pi. 1; reprinted from Trans. Canad. Inst., 8 {1909), III, 

 No. 18, pp. 403-Jt22, pi. 1). — The distribution of a number of the muscle con- 

 stituents was studied microscopically by the use of stains which imparted char- 

 acteristic colors to each. The data reported have to do chiefly with the micro- 

 chemistry of muscle of Insecta and Crustacea. 



ANIMAL PRODUCTION. 



Report of the assistant animal husbandman, E. G. Ritzman {Porto Rico 

 Sta. Rpt. 1908, pp. 37-39). — This report contains brief notes on the live stock 

 industry in Porto Rico and methods of caring for different farm animals at the 

 station. 



The exportation of cattle from Porto Rico to the neighboring islands has 

 gradually diminished, but the quality of the stock kept on the island has some- 

 what improved. In attempting to increase the size of the horses and mules 

 some good results have been obtained by the importation of saddle-gaited and 

 trotting-bred stallions. It costs less to keep horses and mules at the station 

 than in the States. Two horses with very little exercise received 2 lbs. each 

 of oats per day and 2 smaller ones received only 1 lb. per day, with Para grass 

 for roughage. The mules, which are constantly worked, received 3 lbs. of oats 

 daily in addition to the Para grass. Silage from Para grass has also been fed 

 to the mules and cattle. When sprinkled with about 1 liter of cane molasses 

 diluted with water it is eaten with relish, but without molasses they do not 

 seem to care for it. 



