The determiners of cellulose structure as seen in the cell-wall of cotton hairs

Abstract

This analysis of cell-wall structure as seen in cotton hairs began with the inference that diurnal growth rings existed therein. After this inference had been confirmed* it was shown that spiral structures common to all the growth rings were present, and that these were of at least two kinds, quick or “pit" spirals and slow spirals corresponding to objects figured by De Mosenthal.§ In our last communication we concluded that these two kinds of spirals might sometimes be independent of one another; but we now retract this conclusion in the light of results obtained by the improved micro-physical technique which we have substituted for the crude and difficult focussing method formerly employed. In the present communication we propose to study the origin of these spiral structures and to suggest some bearings of our results on problems relating to the molecular structure of cellulose. We abstain at present from extending our studies to comparisons with other plant cells. Before proceeding to the analysis itself we may perhaps mention one side issue of this investigation which affects many calculations about cell-walls. The spiro-fibrillar structure formerly described evidently suggests that the wall is a sponge-like structure with (in the dry state) free air spaces therein. We have ample evidence that this is so, and that the specific gravity of cotton cellulose cell-walls, in their natural condition, is somewhere round 0·90 to 1·10, instead of having the value of 1·55 commonly accepted for the cotton cellulose itself; but the accurate determination of the mean cross-sectional area of the undamaged hair at any fixed temperature and humidity is a matter of exceptional physical difficulty, and is being made the object of an elaborate separate investigation in our laboratory. Meanwhile, it is clear that no accepted values, nor calculations based thereon, are at all reliable.