314 BOTANICAL GAZETTE [November 



Historical 



The first chemical analysis of Amaranthus was made by 

 Boutin (i), a French chemist, in 1873. Housewives of that time 

 were using these plants to clean their cooking utensils. This fact 

 gave it some commercial importance and brought it to the atten- 

 tion of chemists. It was thought that the ability to "cut grease" 

 must be due to acids in the plant. To verify this Boutin inciner- 

 ated 100 gm. dry weight of the entire plant, and obtained 16 gm. 

 residue. Water was added to leach out the soluble salts. The 

 soluble portion weighed 8 gm. He called this potassium carbonate, 

 and calculated the equivalent weight in grams of potassium nitrate, 

 and found it to be 1 1 . 68, or 1 1 . 68 per cent. Boutin concluded that 

 this plant was neutral in reaction on account of the presence of the 

 neutral salt KNO3 (as a matter of fact this plant is acid in reaction). 

 Later (2) he made analyses of the other species of Amara?ithus by 

 the same method, to determine the amount of KNO3. The result 

 of his analysis was as follows: A. atropurpureus contains 22.77 

 per cent KNO3 (one kilogram gives 31 gm. N and 103.5 gm. K); 

 A. Blitum contains 11 .68 per cent KNO3; A. ruber contains 16 per 

 cent KNO3 (one kilogram gives 22 gm. N and 72 gm. K). It is 

 evident that Boutin's method is not an accurate quantitative 

 method of determining the amount of nitrate present. On the 

 other hand, he denionstrated by other quahtative methods that 

 the several species of A?naranthus studied contain a large amount 

 of potassium nitrate. Brosset (3) suggests the use of these plants 

 as a fertilizer. 



Pammel and Dox (15), in 1917, made microchemical tests of 

 three common pigweeds, A. hlitoides, A. graecizans, and A. retro- 

 flexus, and found them to contain abundant starch, some protein, 

 and a little fat. In addition they made the Kjeldahl- Gunning 

 nitrogen determination and found these species to have 1.88, 2.32, 

 and 2.49 per cent of nitrogen. Multiplying by the factor 6.25, 

 they obtained 11.75, i4-52, and 15.59 P^i" cent of protein respec- 

 tively. 



Harding and Egge (8) made an analysis of the seeds of A . retro- 

 flexus for fats, protein, starch, sugars, hemicellulose, crude fiber, 

 and tannin. 



