20 MANUAL OF TROPICAL AND SUBTROPICAL FRUITS 



and the Canary Islands. In the Philippines its culture has 

 been established since the American occupation, many varieties 

 having been introduced by the Bureau of Agriculture. 



While it will thus be seen that the avocado has spread from 

 its native home entirely around the globe, it is still most abun- 

 dant, and of the greatest importance as a food, in tropical 

 America. Throughout Mexico, Central America, and the West 

 Indies seedlings are common in dooryards, thriving with 

 practically no attention and yielding generously of their delicious 

 and nourishing fruits. Rarely in these countries, however, 

 has the avocado been developed as an orchard crop ; but this 

 is not surprising in 'view of the fact that orchards of fruit- 

 trees are almost unknown in the tropics. 



COMPOSITION AND USES OF THE FRUIT 



Due to the investigations of M. E. Jaffa and his associates 

 at the University of California, much light has been thrown 

 on the food value of the avocado in recent years. The following 

 table shows the composition of several well-known varieties, 

 one of each of the recognized horticultural races, and the 

 hybrid Fuerte. In presenting this table, which is based on 

 the work of Jaffa, it is necessary to explain that the proportions 

 of the constituents have been found to change in each variety 

 according to the degree of maturity of the fruits. They may 

 fluctuate also in different years. Variation is particularly 

 noticeable in regard to the fat-content. For example, in 

 specimens of the Chappelow examined at different times, the 

 percentage of fat ranged from approximately 14 to 30, while 

 in specimens of the Challenge it ran from 3 to 17. Fruits 

 showing the lowest percentages were immature at the time the 

 analyses were made, but they were no more so, probably, than 

 many which are put on the market. Up to a certain point, 

 the fat-content increases with the maturity of the fruit; after 



