truncate at the other extremity; the hilum, when perfect, is circular; but it is often cracked, when it appears as a slit, cross, or star. Surrounding the hilum, a few indistinct rings may usually be perceived in some of the granules. Examined with the polariscope, the particles usually exhibit a black cross, the hilum being the centre (fig. 116). THE ADULTERATIONS OF SAGO. The principal adulteration of sago flour and of granulated sago is with potato starch. Frequently a factitious sago prepared from potato starch is substituted for true sago. Fig. 116. ODS SAGO Starch. Magnified 225 diameters. Pereira has the following remarks in relation to factitious sago :'This is prepared in both Germany and in France, at Gentilly near Paris, with potato starch. It occurs both white and coloured. I have two kinds of white factitious sago, one small grained, the grains of which are scarcely so large as white mustard seeds; the other large grained, the grains of which are intermediate in size be tween white mustard seeds and coriander seeds. The first I met with in English commerce; for the other I am indebted to Professor Guibourt. 2 'I have also two kinds of coloured factitious sago, both large grained; one red,' the other brownish, and somewhat resembling brownish pearl sago.' Starch granules of SAGO, altered by heat, as in making granulated sago. Magnified 225 diameters. Pereira also states that he received from Prof. Guibourt samples of Sagou des Maldives de Planche, donné par lui,' and 'Sagou de la Nouvelle Guinée; donné par lui,' and that he found them to be factitious sages prepared from potato starch. The grains of the New Guinea sago were bright red on one side and whitish on the other. Results of the examination of samples.-Of thirty samples of granu Fig. 117. lated sago submitted to examination, five were found to be factitious, and to consist of potato flour. 1 'This is perhaps the kind mentioned by Planche, as being falsified sago coloured with cochineal.' 2 This is perhaps the brown sort of German sago made from potato starch, and said by Dierbach to be coloured with burnt sugar.' THE DETECTION OF THE ADULTERATIONS OF SAGO. The microscope can alone detect the adulterations of sago flour and granulated sago, and especially can distinguish factitious from genuine sago. The characters of sago starch have already been described and figured, as also have those of potato, at p. 371 ; in granulated sago, whether true or false, the granules are of course much altered (fig. 117) those of potato are swollen, irregular in shape, sometimes ruptured, and the striæ effaced, &c. (fig. 118). Factitious sago, composed of potato flour. Magnified 225 diarneters. CHAPTER XVI. TAPIOCA AND ITS ADULTERATIONS. DEFINITION OF ADULTERATION, Any other starch or farina than that of Tapioca, or any added vegetable or mineral substances. THE articles known as Cassava meal and bread, Cassava, Tapioca, or Brazilian arrowroot and Tapioca, are obtained from different species Fig. 119. Starch granules of MANIHOT UTILISSIMA, or Tapioca. Magnified 225 diameters. of the geuus Manihot, one of the Euphorbiacee. One of these is M. utilissima, the bitter Cassava, a native of the Brazils, where, as well as in other parts of South America, it is cultivated. The starch is associated in the large tuberous root with a poisonous milky juice containing hydrocyanic acid and a bitter acrid principle. Another species is Manihot Aipi, or sweet Cassava, the juice of the root of which is not poisonous. A third species is M. Janipha, the root of which is also devoid of poisonous properties. Cassava meal is prepared as well from the bitter or poisonous species as the sweet and innocuous: the root is grated, and the pulpy mass subjected to pressure in bags under water to get rid of the juice; the residue is spread out on iron plates in layers of one or two inches in Starch granules of Tapioca, altered by the heat employed in its preparation. Magnified 225 diameters. a thickness, and is dried into cakes, when, after being pounded, it constitutes Cassava meal, and of this the bread is made. The expressed juice deposits after a time the farina or starch, which in this state is called tapioca meal, and this, after being dried upon hot plates, constitutes granular tapioca. Characters of the starch corpuscles.-Examined under the microscope, the granules are seen to be of small size, for the most part single, but sometimes and in the plant itself always united into compound grains, each composed of two, three, or four granules. Hence, like |