| Date | Age of Crop | Plot | Dry Weight | Furfural p.ct. of dry weight(a) | Permanent tissue p.ct. dry weight | Furfural from permanent tissue | ||
| P.ct. of tissue | P.ct. of entire plant | Ratio a : c | ||||||
| May 7 | 6 weeks | 1 | 19.4 | 7.0 | 53.4 | 12.7 | 6.8 | 1.03 : 1 |
| 6 | 14.7 | 7.0 | 55.9 | 10.3 | 5.7 | 1.23 : 1 | ||
| June 4 | 10 weeks | 1 | 17.6 | 7.7 | 52.9 | 11.6 | 6.1 | 1.26 : 1 |
| 6 | 13.5 | 8.1 | 58.5 | 13.4 | 7.8 | 1.04 : 1 | ||
| July 10 | 15 weeks | 1 | 42.0 | 9.0 | 65.7 | 9.8 | 6.4 | 1.40 : 1 |
| 6 | 32.9 | 10.6 | 65.7 | 12.5 | 8.2 | 1.30 : 1 | ||
| Cut Aug. 21 | 21 weeks | 1 | 64.0 | 11.9 | 70.0 | 14.5 | 10.1 | 1.18 : 1 |
| 6 | 64.6 | 13.4 | 70.5 | 15.0 | 10.6 | 1.26 : 1 | ||
| Carried Aug. 31 | 22 weeks | 1 | 84.0 | 12.7 | 75.0 | 16.5 | 12.4 | 1.02 : 1 |
| 6 | 86.4 | 12.4 | 78.4 | 15.1 | 11.8 | 1.05 : 1 | ||
| BARLEY CROP, WOBURN, 1895. | ||||||||
| May 15 | 7 weeks | 1 | 20.6 | 6.6 | 53.9 | 10.2 | 5.5 | 1.20 : 1 |
| 6 | 17.8 | 5.8 | 56.7 | 9.6 | 5.4 | 1.07 : 1 | ||
| June 18 | 12 weeks | 1 | 34.6 | 8.0 | 38.2 | 14.7 | 5.6 | 1.42 : 1 |
| 6 | 33.4 | 7.6 | 44.5 | 15.0 | 6.7 | 1.14 : 1 | ||
| July 16 | 16 weeks | 1 | 52.8 | 12.1 | 55.6 | 16.3 | 9.1 | 1.33 : 1 |
| 6 | 54.4 | 10.6 | 46.2 | 19.1 | 8.8 | 1.20 : 1 | ||
| Aug. 16 | 20 weeks | 1 | 66.8 | 9.2 | 49.1 | 17.0 | 8.3 | 1.10 : 1 |
| 6 | 65.0 | 9.8 | 49.8 | 19.1 | 9.4 | 1.04 : 1 | ||
| Sept. 3 | 22 weeks | 1 | 84.3 | 10.4 | 45.7 | 17.6 | 8.0 | 1.31 : 1 |
| 6 | 86.3 | 10.2 | 45.3 | 17.3 | 7.8 | 1.30 : 1 | ||
The variations exhibited by these numbers are significant. It is clear, on the other hand, that the assimilation of the furfuroids does not vary in any important way with variations in conditions of atmosphere and soil nutrition. They are essentially tissue-constituents, and only at the flowering period is there any accumulation of these compounds in the alkali-soluble form. It has been previously shown (ibid. 27, 1061) that the proportion of furfuroids in the straw-celluloses of the paper-maker differs but little from that of the original straws. For the isolation of the celluloses the straws are treated by a severe process of alkaline hydrolysis, to which, therefore, the furfuroid groups offer equal resistance with the normal hexose groups with which they are associated in the complex.
The furfuroids of the cereal straws are therefore not pentosanes. They are original products of assimilation, and not subject to secondary changes after elaboration such as to alter either their constitution or their relationship to the normal hexose groups of the tissue-complex.