August 31, 18S3.] 



SCIENCE. 



291 



The sotol, a Mexican forage plant. 



BT CLIFFOKD KICHAUDSON OF WASUISaTON, D.C. 



This plant, Dasylinion texanum, grows wild and 

 extensively on the borders of the Kio Grande and 

 elsewhere in Texas, and in Mexico, on a rocky and 

 gravelly soil. The plains covered with it look like a 

 vast cabbage-field. Sheep feeding on it go withont 

 water for many weeks. Only the bulb is eaten. It 

 is split open by the shepherd, who carries a knife for 

 the purpose. Mexican* eat the bulb after roasting or 

 baking it in pits. Also a liquor is obtained from it, 

 by fermenling and distilling after roasting, called 

 'sotol mescal,' and possessed of highly intoxicating 

 powere. 



The plant is described in Watson's Revision of the 

 North-American LilLiceae. About IS per cent of 

 sugar can be obtained from the outer husks; in the 

 interior, more than 10.5 per cent exists; and in the 

 whole head of the plant there is probably more than 

 15.5 per cent of sugars. No starch seems to be pres- 

 ent. 



A proximate analysis of the soft interior of the 

 head gave 17 percent sugars: 65 per cent of this 

 soft substance in the he.ad, when fresh, is water. 



As a food-plant in dry districts, the sotol is of 

 great value; as a fibre-producing plant, it will not be 

 of any importance, owing to the shortness of the 

 cells. 



American butters and their adulterations. 



BY H. W. WII.KY OF WASniXOTON, D.C. 



A SF.iiiES of elaborate experiments and analyses of 

 various samples of butter, oleomargatine. tallow, and 

 lard, have been made by Professor Wiley, chemist 

 of the U.S. department of agriculture. The paper 

 contained a description of Professor Wiley's method. 

 He takes a weighed quantity of the butter, puts it in 

 a sand-bath, and drirs for two hours at 100°. The 

 curd or c.aseine is determined by ignition : five gr.iins 

 are used fur the purpose. Dry combustion in a tube 

 is difficult and unsatisfactory: he therefore uses the 

 moist-combuslion method, with permanganate and 

 nesslerizing. The amount of salt he considers im- 

 portant. It is usually determined by i.iinilion, and 

 weighing the residue; but he found that so much 

 chlorine was thereby lost, that tlie result was not 

 trustworthy. Re washes the butter by shaking it in 

 a sepaialing funnel with hut water, and then deter- 

 mines the chlorine with standard silver nitrate and 

 potassium bichromate as an inilicalor. 



Professor Wiley has devised several novelties for 

 these anal> ses. One of the neatest is for ascertain- 

 ing the meliing-point. The butter is packed in a 

 U-shaped tube, of which one leg is longer than the 

 other. The lube is placed upriiiht in a vessel con- 

 taining sufficient mercury to overflow the top nf the 

 tube. This vessel is placed in another containiiig 

 water, and heat is applied beneath. The water, 

 heated, in tvun heals tlie mercury surrounding the 

 tube, unlil the ci>nients of the tube are melted. As 

 soon as the luelling takes place, the melted matcriul 



leaves the tube, and floats on the pnrface of the mer- 

 cury. Another methiiil consisted in lading ))laiinum 

 wires upon the .sample of butler, etc., heating the 

 wires, and noting the heat required to cause them to 

 disappear by sinking into ilie sample. These meth- 

 ods determined not only the meliing-point if .samples 

 of butter, oleomargarine, tallow, and lard, but also of 

 the fatty .acids. But the variaiions in the melting- 

 piiint of genuine butler are »o wide, that no certain 

 conclusion can be ariived at by coniparis'in with 

 melting-point of oleomargarine, etc., to test the 

 question of genuineness. Thus it was found that 

 lirsl-rate butter from an Alderney cow at one lime, 

 owing to special feeding, had a higher meliing-poiiit 

 than oleomargarine; while a few weeks laier, with 

 different food, the same cow supplied milk from 

 which was made butter with a lower melting-point 

 than oleomargarine. 



In regard to other tests, concerning which full 

 details were given in the paper, it may be briefly 

 stated, that, as a general rule, the amount of casidne 

 present in pure butter is much greater than in oleo- 

 margarine. The specific gravity of genuine butter is 

 lower. The saturation co-cflScienl for the insoluble 

 acids in the genuine butter is low, in the imitations 

 it is high. Professor Wiley seems to place more reli- 

 ance on tests for saturalion co-efiicient than on other 

 methods. The soluble fatty acids in pure butter 

 range from three to five per cent ; while in oleo- 

 margarine, tallow, etc., they are eitlu-r absent, or 

 show a mere trace. The author also called attention 

 to polarization tests. The genuine butler gives a 

 uniform field in polarized light: oieoniargarine gives a 

 field with mottled and crystalline structure. He had 

 made no analysis of butter known or suspected to be 

 adulterated by mixture. He considered it unwise to 

 decide the question of penuinehess from any one of 

 the conslituenis or eondilions of a sample; believing 

 that all the different tests should he brought to bear. 

 He presented elaborate tab'es of analyses of different 

 kinds of butler, etc : specifying for eich the place of 

 purchase, name sold by, price, color, percfntage of 

 water, of caseine, of salt, specific gravity at 40°, melt- 

 ing and solidifying points, pircentage of polnble and 

 of insoluble acids, and the melting and solidifying 

 points and the saturation equivalent of the insoluble 

 acids. 



The discussion respecting the analysis of butler 

 which was brought about by this paper revolved 

 around the question of the value of the dala pre- 

 sented for the practical work of the detei-inination of 

 actual proportion of adulteration. Mr. Noyes held 

 that the variati^ins in pure butlers in s|n cific gravity, 

 in melting-point, in saturation co-efficieiil, and in 

 c.iseine, as doiermined by Professor Wiley, would be 

 of little value except in cases where the ailulteration 

 was very great. Mr. Springer held that the principal 

 conslitui'iit to be taken into account in the deiermi- 

 nalion of adulteration was the amount of casi'ine. and 

 that allhoii2h ihere were some difficulties in the way 

 of iis accurate determinaiion, thcv might be removed, 

 and he should then have more faith in iliis than in 

 the coDiparison of other data. He suggested that the 



