. Contributions from the Botanical Laboratory, vol. 7. Botany; Botany. Fig. 5. The elementary body of cellulose (after Meyer and Mark) aside from that, they may have any position or orienta- tion and decidedly lack the regularity of bricks m a wall. Any attempt to graphically represent the links, chains and micellae in a block of cellulose, while accurate in part is going to necessitate the addition of details which we really know little or nothing about. Fig. 6 is such an No. 688] CONTRACTILITY OF PROTOPLASM 423. Fig. 6. A number of cellulose micellae, the interior of one of which ia, in part
. Contributions from the Botanical Laboratory, vol. 7. Botany; Botany. Fig. 5. The elementary body of cellulose (after Meyer and Mark) aside from that, they may have any position or orienta- tion and decidedly lack the regularity of bricks m a wall. Any attempt to graphically represent the links, chains and micellae in a block of cellulose, while accurate in part is going to necessitate the addition of details which we really know little or nothing about. Fig. 6 is such an No. 688] CONTRACTILITY OF PROTOPLASM 423. Fig. 6. A number of cellulose micellae, the interior of one of which ia, in part, exposed and enlarged to show the chains of glucose residue units: a - primary valency forces, h - secondary association forces, c - tertiary micellar forces. attempt and should be regarded as approaching accuracy in so far as it indicates that the chains are of different lengths, that the crystallite has an internal arrangement of chains which is orderly, that it is very long compared with its diameter and that its position is random except that the long axes of the crystallites are parallel. The forces which hold the units of a chain together are primary valence ones. Those which hold the chains to- gether in a bundle are of a secondary type. There must also exist residual surface forces which tie the micellae one to another in a block of cellulose. These are of a ter- tiary nature and must be capable of considerable adjust- ment since they are firm in a xerogel, less firm in an elastic jelly and loose in a liquid cellulose dispersion which though it flows smoothly yet retains some elas- ticity. Herzog'* states that in many cases a number of micellae come together to build up larger structural units which he calls secondary particles. If this is true then we are dealing with forces of still another and weaker order of magnitude. The naming of the several types of forces which hold the links, chains and micellae together is somewhat arbi- trary with each worker. Wise"* r
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