52 STUDIES ON APPLES. 



to 20, inclusive) are much more uniform than in the charts just preced- 

 ing, which represent the composition of the summer apples. The 

 work on the winter apples began on June 16, 1903, and extended until 

 November 5, 1903. These curves illustrate much better the early life 

 history of the fruit than those representing the work of the previous 

 year. As in that year, the sucrose curve is almost exactly the reverse 

 of the starch curve. This is only true, however, after the maximum 

 content of starch has been reached, which was between June 30 and 

 July 28 with the Ben Davis apples, on July 28 with the Huntsman 

 apples, and on June 30 with the Winter Paradise apples. It must be 

 understood that no one of these dates is suggested as the exact date of 

 the maximum content of starch in the apple. It is only intended to 

 represent the maximum content of starch on the various dates when 

 the apples were examined. On the whole, however, the maximum 

 content can not have varied greatly from the date given, and the 

 maximum percentage determined must also be approximately correct. 



The observation as to the uniformity of results applies equally to 

 all of the determinations made. On the date of the first examination- 

 June 16 the content of sucrose based on total solids was 4 per cent. 

 The percentage of sucrose increased regularly until the last examina- 

 tion, which was made on November 5, when it amounted to 25.4 per 

 cent of the total solid content of the apple, the rate of increase being 

 apparently no greater before the maximum content of the starch than 

 afterwards. It would appear that during its own growth and accumu- 

 lation a portion of the starch is converted into sucrose. Unlike the 

 summer apples, the percentage of invert sugar here increased from 

 the date of the first examination to approximately the date of the last, 

 so that even in percentage composition the amount of invert sugar 

 present did not reach its maximum until the maturity of the fruit. 



In all three of the varieties of winter apples studied the percentage 

 of malic acid decreased from the first examination to the full maturity 

 of the fruit. The percentage of total sugar estimated as invert sugar 

 increased steadily from the first examination to full maturity, it is 

 a notable fact that after the maximum content of starch is reached 

 the percentage of starch and invert sugar taken together remains 

 approximately constant. As in the case of the preceding studies, the 

 'average com position of the three varieties of winter apples has been 

 expressed in the form of a composite chart which is given in figure 20. 



In many respects it was considered that a graphic statement showing 

 the actual increase in weight of the various constituents of the apple 

 determined would have a more definite meaning than the changes in 

 chemical composition on the percentage basis. Before examination 

 each sample was weighed so that the data were secured for this calcu- 

 lation. In figures 21 to 28 the changes of the apples just considered, 

 both summer and winter varieties, are represented in terms of grams 

 per apple. 



