18 



REPORT OF THE FIRST SEMI-ANNUAL MEETING 



stearin having the higher melting point. Therefore the larger the 

 proportion of olein contained in a fat, the softer it is, while the 

 greater the proportion of stearin, the higher its melting point, In 

 oHve oil the proportions are just reversed, the average sample con- 

 taining 28 per cent of palmitin and stearin and 72 per cent of olein, 

 which accounts for its greater liquidity. The oils from different 

 varieties of olives vary considerably in the percentage of olein 

 present ; some are therefore more liquid than others. Whether this 

 same variation occurs in the oil of different varieties of avocados 

 has not been investigated, but it is not likely to be sufficient to 

 materially affect the quality of the product. In his book on "Vege- 

 table Fats and Oils," 1902, Andes includes avocado oil in the list 

 of fats of no commercial importance. In foreign countries it is 

 known under various names, such as Huile de avocatier, Avocato 

 oil, alligator pear oil, grasa persea,.and advogatofett. It has been 

 used medicinally to a small extent in Brazil and elsewhere. Alli- 

 gator pear soap is manufactured in Guatemala and can l)e pur- 

 chased in this country. Cheaper forms of fat, however, are ordi- 

 narily available for soap-making, and such a product probabl}^ con- 

 tains only a small percentage of avocado oil. According to Collins 

 (Bulletin 77, U. S. D. A.), the ladies of Guatemala sometimes ex- 

 tract oil from avocados by pressure. They never use it in cooking, 

 but say it is fine for the hair. 



In the preliminary experiments at the University by Mr. Mitra, 

 a graduate student, it was found difficult to press out the oil in an 

 ordinary press, since the flesh is so soft and fine the two will not 

 separate readily. The slices of flesh were therefore dried in an 

 oven, the pieces ground up and then put in a press. By the ordinary 

 method of pressure it was found that only about 15 per cent of the 

 oil could be obtained. The resulting oil, samples of which I have 

 with me, is fairly clear, dark green in color, somewhat bitter but 

 not unpleasant to the taste. It is doubtful whether the oil will be 

 of much commercial value. Larger quantities may be extracted by 

 ether, gasoline, or other solvents, but the resulting oil is affected 

 both in color and flavor. The process of extraction is a little more 

 expensive than by pressure. 



Some experiments have been made in the production of a paste, 

 but they have not progressed sufficiently to be conclusive. This 

 form of by-product looks promising, however, its success depend- 



