1 Ding. Polyt. Journ., 211, 78; Jahresb. d. Chem.. 1874, 1043.

2 Ding. Polyt, Journ., 215,84; Am. Chemist, 6, 220.

3 Arch. Pharm. [3], 8,298; Jahresh. .1. Chem., 1876, 1021.

4 Moniteur Scientific [3], 10,1339; Jahresh. d. Chem., 1880, 1220.

5 Mitt. a. (1. Pharm. Inst. n. Lab. f. Angew. Chem. Erlangen, Heft:3, 1 to 56.

The quantitative estimation of chicory or of the amount of coffee in mixtures can not be made with certainty, and in all such estimations only an approximate percentage content can be stated. The proportion of chicory in a mixture is usually calculated from the specific gravity of an extract made under definite conditions, comparison being made with a coffee extract prepared under the same conditions. In other methods a comparison is made of the depth of color of infusions under certain standard conditions.

According to A. H. Allen' the following method gives fairly good results:

A weighed portion of the finely ground sample is boiled with water, filtered, and the residue washed with hot water until the nitrate amounts to 10 cc. per gram of the sample taken. The specific gravity of this extract is then determined and the chicory calculated by the formula.

c = (1.023 - d) 100 14.5. in which c is the per cent of coffee, d the density of the extract. Allen found the mean density of the 10 per cent decoction of a large number of coffees to be 1.0085, and of chicory under the same conditions, 1.023.

The presence of cereals or other foreign matter would of course render this method unreliable.

Preuier2 states that Chicory may bo estimated by sifting a definite weight, approximately 2 grams of the ground mixture; the powder which passes the sieve is always coffee. The larger grains are macerated with cold water for some hours, then thrown on a piece of stretched cloth and rubbed with a pestle. The chicory will pass through the cloth. The residue left on the cloth is now dried and weighed with the powder.

This is evidently a very rough method.

Another method for the estimation of chicory, and as rough as the above, is that of C. Draper.5 In this method a glass similar in shape to a percolator is employed. The stem is graduated and is sealed at the lower end. This apparatus is partly filled with cold water, and a definite volume of the ground sample is slowly distributed upon its surface. The chicory sinks to the bottom of the water and its depth is noted in the graduated tube.

The writer has found pure coffee, evidently overroasted, that would sink in water. Other writers have also found coffee that would sink, after a few minutes, in water. In case the adulterant has been treated with a fat, it would be liable to float instead of falling to the bottom of the apparatus. Chicory is often so treated.

The cells, milk vessels, etc., are well illustrated in the Plate xlv. The milk vessels, vasa lacticentia, should be carefully studied, since their peculiarities will usually serve to distinguish chicory from other roots liable to be employed as adulterants.

Mangoldwurzel. - This is a root much used abroad for cattle feeding.

1 Chemical examination of coffee. - Chem. News, 29, 129, 140, 167, 189, 221. Op. tit. 30, 2. 2 Journ. Pharm. Chim. [5] 1, 222-224; Journ. of the Chem. Soc. 1880,514. 3 Philos. Mag. 38, No. 228, 104; Zeitsch. f. anal. Chem. 7, 388.

According to Hassall,1 the large size of the cells and the absence of milk vessels distinguish this root from chicory.

Cereals, leguminous seeds, and acorns. - Judging from these investiga-tions the adulteration of coffees in this country with chicory is not as common as with cereals, pease, beans, etc. These latter substances, in general, are detected by the presence of starch and are finally identified by their structures as shown by the microscope.

The following method of A. H. Allen is probably the best for the detection of starches, chemically, in adulterated coffees:

Boil a portion of the powdered sample with water and filter; cool the filtrate, acidulate with sulphuric acid; add a strong solution of permanganate of potassium, small quantities at a time, until the coloring matter of the original extract is discharged; test for starch as usual with iodine.

Starch may be easily detected in the finely powdered sample, mounted in Canada balsam, on examination by the microscope, with polarized light. Starch, when examined as above, shows a dark cross on a white field.

In Part II of this bulletin (Plates XIII to XXVIII a number of starches are illustrated as shown by the microscope with polarized light and plain illumination. In the identification of starches it is well to have a series of freshly-prepared slides of the materials from known sources for purposes of comparison.

Sufficient of the original structures of the cereals or leguminous seeds will usually remain for their identification with the microscope. In this work it is well to have a series of slides prepared from the raw and roasted materials for comparison.

The following statement of the percentage of ash in cereals is given for comparison with that of coffees. The mean ash of the cereals given is considerably lower than that of coffee.

Ash 2 Of Cereals - (American)

Carina seed, etc. - M. Mansfeld3 reported the presence of c anna seed in a coffee, and in an examination made in Austria, sawdust, oak bark, baked liver, etc. Hassallteration of coffees. None of these substances, except sawdust, have been detected in the investigations in connection with this report. Chemical tests are not applicable. On the detection of a foreign matter, which is not among those described, evidently the only course to pursue is to prepare slides for microscopic comparisons with others of known composition.

4 mentions the use of sawdust, etc., in the adnl1 Food, Arthur H. Hassall, Lougmans, Green & Co., London, p. 167. 2 Dictionary of Applied Chemistry, Thorpe, 1, 490. Analyses by Clifford Rich-ardson, U. S. Department of Agriculture. 3 Rev. int. Scion, et Pop. des Falsification, 4, 40. 4 Hassall, Food, p. 159.