6 BULLETIN 717, U. S. DEPARTMENT OF AGRICULTURE. 



A review of the literature of protein chemistry shows that while in 

 general they are of a very complex structure the vegetable proteins 

 yield on hydrolysis nearly all of the 16 amino acids which normally 

 result from the decomposition of protein material. While all of these 

 amino acids supply elements of value for food purposes, the results 

 of carefully-controlled feeding experiments show conclusively that 

 the dietary value of the different amino acids varies materially. 



No resume of the literature of protein and amino acid chemistry 

 would be complete without special reference to the extensive investi- 

 gations of Osborne ^ to whom the present interest in this subject is 

 in no small measure due. In this brief discussion of amino acids it is 

 impossible to more than refer to the investigations which have been 

 carried out by Osborne et al.^^ Henderson and Dean,^ Kauffmann/ 

 Cohnheim,^ Abderhalden and coworkers/ Henriques/ Willcock and 

 Hopkins,^ Miiller,^ Rona and Mtiller,^" Michaud/^ McCollum et al./^ 

 Folin and Denis/^ Hart and assistants,^* Kajiura/^ Wheeler/*' 

 Underliill/'^ Nollau and Kastle/^ Johns/^ and Geiling/*' to determine 



1 Amer. Chem. Jour., 13 (1891), pp. 327-347, 385-414; 14 (1892), pp. 212-224, 62&-661, 662-6S9. Amor. 

 Chem. Jour., 19 (1897), pp. 236, 237. Jour. Amer. Chem. Soc., 16 (1894), pp. 633-643, 703-712, 757-764; 17 

 (1895), pp. 429-448, 539-567, 587-603. 19 (1897), pp. 525-532. Ztschr. Physiol. Chem., 33 (1901), pp. 225-239, 

 240-292. Amer. Jour. Physiol., 5 (1901), pp. 180, 181. Jour. Amer. Chem. Soc, 24 (1902), pp. 140-167. 

 Proc. Soc. Expt. Biol, and Med., 5 (1908), pp. 105-107. Science, n. ser., 28 (1908), pp. 417-427. The Vege- 

 table Proteins [London], Longmans, Green and Co., 1909. Ergeb. Physiol., 10 (1910), pp. 47-215. 



2 Jour. Amer. Chem. Soc, 16 (1894), pp. 778-785; 18 (1896), pp. 536-542, 542-558, 575-582, 583-609, 609-623; 

 19 (1897), pp. 454-482, 482-487, 487-494, 494-500, 509-513; 20 (1898), pp. 348-362, 362-375, 393-405, 406-410, 

 410-419, 419-428; 22 (1900), pp. 379-413; 25 (1903), pp. 323-353, 474-478, 837-842, 842-848, 848-853, 853-855. 

 Amer. Jour. Physiol., 13 (1905), pp. 35-44, 436-447; 14 (1905), pp. 151-171, 259-286; 15 (1906), pp. 333-356; 

 17 (1906), pp. 231-265; 18 (1907), pp. 123-128, 295-308; 19 (1907), pp. 53-60, 117-124, 468-474, 475-481; 20 (1908), 

 pp. 470-476, 477-493, 494-499; 22 (1908), pp. 362-372, 423-432; 23 (1908), pp. 180-200. Jour. Biol. Chem., 3 

 (1907), pp. 213-217, 219-225; 5 (1908), pp. 187-195, 197-205. Amer. Chem. Jour., 15 (1893), pp. 392-471. 

 Jour Biol. Chem., 10 (1911), No. 10, pp. 303-325; 12 (1912), No. 3, pp. 473-510, figs. 26; 13 (1912), No. 2, pp. 

 233-276, figs. 21; 14 (1913), No. 5, pp. 481-487; 17 (1914), No. 3, pp. 325-349, figs. 8; 18 (1914), No. 1, pp. 1-16, 

 figs. 6; 20 (1915), No. 3, pp. 351-378, fig. 10; 22 (1915), No. 2, pp. 241-258, fig. 1; pp. 259-280; 25 (1916), No. 1, 

 pp. 1-12, figs. 4; 29 (1917), No. 1, pp. 69-92, fig. 1. 



3 Amer. Jour. Physiol., 9 (1903), No. 6, pp. 386-390. 



* Arch. Physiol. [Pfluger], 109 (1905), No. 9-10, pp. 440-465. 



6 Hoppe-Seyler's Ztschr. Physiol. Chem., 49 (1906), No. 1, pp. 64-71. 



6 Iloppe-Seyler's Ztschr. Physiol. Chem., 47 (1906), No. 4-6, pp. 354-358; 51 (1907), p. 232; 77 (1912), No. 1, 

 pp. 22-58; 81 (1912), No. 4, pp. 323-328. Synthese der Zellbaustine in Pflanze und Tier. [Berlin, Julius 

 Sprmger], 1912, p. 128. 



^ Hoppe-Seyler's Ztschr. Physiol. Chem., 49 (1906), No. 2-3, pp. 113-123; 60 (1909), No. 2, pp. 105-118. 



8 Jour. Physiol., 35 (1906), No. 1-2, pp. 88-102. 



9 Arch. Physiol. [Pfluger], 112 (1906), No. 5-6, pp. 245-291, pis. 2, fig. 1. 



10 Hoppe-Seyler's Ztschr. Physiol. Chem., 50 (1907), No. 4-5, pp. 263-280. 

 Ji Ztschr. Physiol. Chem., 59 (1909), No. 5-6, pp. 405-491. 



12 Amer. Jour Physiol., 29 (1911), No. 2, pp. 215-237. Jour. Biol. Chem., 19 (1914), No. 3, pp. 323-333; 2. 

 (1915), No. 1, pp. 181-230, figs. 42; 20 (1915), No. 3, pp. 415-428, figs. 12; 28 (1916), No. 1, pp. 153-165, figs. 10, 

 No. 1, pp. 211-229, figs. 17; No. 2, pp. 483-500, pi. 1, figs. 12. 



13 Jour. Biol. Chem., 11 (1912), No. 1, pp. 87-95. 



i« Jour. Biol. Chem., 13 (1912), No. 2, pp. 133-153, figs. 4; 19 (1914), No. 3, pp. 373-395, pi. 1, figs. 11. Wis- 

 consin Sta. Research Bui. 17 (1911), pp. 205, pis. 19. Jour. Biol. Chem., 25 (1916), No. 2, pp. 239-260, pis. 9, 

 figs. 9; 29 (1917), No. 1, pp. 57-68, pi. 1. 



15 Bio-Chcm. Jour., 6 (1912), pp. 171-181. 



18 Jour. Expt. Zool., 15 (1913), pp. 209-223. 



1' The Physiology of the Amino Acid.s, F. P. Underhill, New Haven: Yale Univ. Press, 1915, pp. 169, pi. 

 1, figs. 13. 



18 Amer. Jour. Physiol., ,39 (1915-16), No. 2, pp. 162-171, pis. 8. Kentucky Sta. Bui. 197 (1916), pp. 21, 

 pis. 16. 



i» Jour. Biol. Chem., 28 (1916), No. 1, pp. 59-65, 67-75, 77-87. 



" Jour. Biol. Chem., 31 (1917), No. 1, pp. 173-199. 



