20 . CASSAVA. 



In the twenty-eight so-called sweet varieties the hydrocyanic acid 

 ranged from 0.0005 to 0.016 per cent, and more than half of them con- 

 tained 0.002 per cent or less. Referring to the Biloxi results on the 

 corresponding numbers, it will be seen that two-thirds of the samples 

 contained 0.010 per cent or more, and No. 9696, almost the extreme 

 bitter variety at Biloxi, would be classed as sweet at Miami. Variety 

 No. 9699, grown at Miami, which had been brought over as a poison- 

 ous type, contained only 0.018 per cent of hydrocyanic acid, whereas 

 in its native country the same variety, though not from pedigreed 

 cuttings, had shown more than 0.05 per cent of the poison. (See 

 Table VI.) 



A series of the same pedigreed cuttings had been planted at Dania 

 and another series at Lemon City, respectively 20 miles and 5 miles 

 north of Miami. The soil at Dania was black humus known as u glade 

 land, r and the plantings were practically a failure. However, sam- 

 ples, though very small, were taken of all varieties that produced 

 tubers, and these, as a series, were found to be similar in hydrocyanic- 

 acid content to the cassava produced at Miami, varying from 0.0005 to 

 0.011 per cent. By referring to Table VI it will be seen that certain 

 corresponding numbers varied. No. 9685, which contained 0.0005 per 

 cent of prussic acid in Miami, contained 0.010 when grown at Dania, 

 and No. 9691, which contained 0.007 at Miami, showed only 0.0005 at 

 Dania. 



Most of the varieties planted at Lemon City lived and made good 

 yields, the soil at this point being of the same sandy nature as that in 

 Miami. In general the series grown at Lemon City shows the .same 

 content of hydrocyanic acid as that grown at Miami, and in the 

 majority of cases approximately the same results were obtained on 

 corresponding numbers at the two stations. 



At Lemon City the plants, being a year old, were just beginning to 

 put on a spring growth, and it was planned to make a series of analyses 

 which would represent weekly periods of growth to determine whother 

 periodic changes occurred in the hydrocyanic-acid content. The 

 plants \\civ sampled daily and the estimations made in duplicate, the 

 figures obtained being recorded in Table VI. 



