CALIFORNIA AVOCADO ASSOCIATION 



27 



avocado on the same water basis, or upon a water-free basis, the figures 

 would not be so favorable to the avocado, in that the avocado contains less 

 water on the average than do most of the fresh fruits. The above state- 

 ments, however, are made on the fruit as consumed and therefore it can 

 be said that per unit weight of fresh fruit eaten, more mineral matter 

 is ingested with the avocado than with any of the other fruits mentioned. 



Current investigations carried on by such men as McCollum, Osborne, 

 Mendel, etc., have now fully established the fact that animals cannot grow 

 when limited to rations of carefully purified proteins, carbohydrates, fats, 

 and salts. McCollum and Davis have shown that certain fats, as butter 

 fat, egg yolk fat, kidney fat, and some others, contain something which 

 greatly stimulates growth when added to a diet of casein, dextrin, lactose, 

 and a salt mixture of appropriate composition. This substance is present 

 in certain products of plant origin as well. Later they discovered that if 

 the lactose was replaced by dextrin in this ration the addition of butter 

 fat did not induce growth. When this diet, containing butter fat, was 

 supplemented with small additions of the water extract of boiled egg yolk, 

 or water or alcoholic extracts of wheat germ, growth proceeded at the 

 normal rate. They formulated the working hypothesis that in addition to 

 the recognized essential constituents of a successful diet, viz., protein, 

 carbohydrate, fats, and inorganic salts, the growing animal requires two 

 substances, or groups of substances; one, which is soluble in fats, is 

 contained in fats from certain sources; the other, which is soluble in water 

 and alcohol, is found widely distributed both in the animal and the vege- 

 table worlds. 



This Laboratory intends, during the summer, to conduct investigations 

 cn growing animals with avocado oil to ascertain whether it will rank in 

 the positive or negative group as regards its content of this unknown ele- 

 ment necessary for growth. 



It has been shown, as above, that in addition to this fat-soluble ma- 

 terial, there is another water-soluble material that must be associated with 

 the fat-soluble material in order to bring about the best conditions for 

 growth. It has been suggested by McCollum that this unknown element 

 soluble in fat be called fat-soluble A, while the other unknown substance 

 soluble in water which is contained in different plant foods, be termed 

 water-soluble B. If it could be proved that both the fat-soluble A and the 

 water-soluble B were present in the avocado, as they are in the wheat 

 embryo, it would be the highest recommendation for the avocado as a 

 food for the very young. 



FROM SEEDTIME TO HARVEST 

 T. U. Barber, Los Angeles, Cal. 



Selection of Seed. — All fruit growers recognize the value of a strong, 

 healthy root system. Without such a beginning a vigorous, heavy bearing 

 top cannot be developed. With this important fact in mind, we must pay 

 considerable attention to the selection of seeds which are to form the 

 foundation stocks of our orchards. At the present time everything stands 

 in favor of seed from the thin-skinned Mexican fruit — this type is the 

 most resistant to both frost and heat and produces just as fine growth 



