670 ANNUAL REPORT OF THE Off. Doc. 



Lusk. Those cells are from one-one thousand to o^ie-fifteen hun- 

 dredths of an inch in length and about one two thousand five huu 

 dredths of an inch in width. 



If a sample of ground cocoa husks be prepared for microscopic ex- 

 amination as previously described these thick walled cells aod the 

 fibro-vascular bundles composed chiefly of small spiral vessels form 

 very prominent and abundant objects in the field of the microscope. 



If microscopic examination of a sample of chocolate leads one to 

 suspect the presence of an undue proportion of cocoa husks, and no 

 other adulteration is detected, the amount of husk preseot can be 

 calculated by determining the percentage of crude fiber in the 

 sample. Samples of cocoa husks analyzed in my laboratory have 

 yielded ao average of fifteen per cent, of crude fiber. 



Following the method of analysis adopted by the Associatien of 

 Official Agricultural Chemists of the United States, samples of 

 roasted cocoa beans husked and ground in the laboratory have yield- 

 ed about 3.25 per cent, of crude fiber. Similar figures for crude fiber 

 have beeo obtained in many samples of chocolate. 



If chocolate is made from cocoa ribs properly freed from husk, 

 the per cent, of crude fiber will not vary much from 3.25 per cent, and 

 I think this figure can safely be taken as a basis on which to calculate 

 the amount of husk which is to be regarded as an adulterant. To il- 

 lustrate, suppose a sample of chocolate yields on analysis six per 

 cent, of crude fiber and microscopic examination shows no foreign 

 matter other than cocoa husks. In this case the excess of husk in 

 the sample is the amount required to raise tlie percentage of crude 

 fiber from three and one-fourth per cent, to six per cent. 



To produce a chocolate containing six per cent, of crude fiber 

 would require the admixture of thirty-six pounds of pure cocoa ribs 

 (three and one-fourth per cent, crude fiber) and eleveo pounds of 

 cocoa husks (fifteen per cent, crude fiber). Such a chocolate might, 

 therefore, be reported as adulterated with twenty-three per cent, of 

 cocoa husks. 



(6) THE FAT OF THE COCOA BEAN. 



Cocoa butter is obtained as a by-product in the manufacture of the 

 so called breakfast cocoa. On account of the large amount of fat 

 entering into their composition, roasted and husked cocoa beaos, 

 when ground at a comparatively warm temperature yield a thick 

 chocolate colored liquid. This liquid consists of the melted cocoa 

 fat in which are suspended the finely divided tissues and other pro- 

 ducts of the cocoa bean. When this liquid is poured into moulds 

 and cooled, the product is chocolate. In order to obtain cocoa but- 

 ter, the liquid is placed in canvas bags and subjected to pressure. 



