THE PRINCIPAL TISSUES. T5 



To examine fibrous tissue it is only necessary to make thin longitudi- 

 nal slices of the stems of woody plants e.g., Acer, Pirus, etc. and to 

 heat for a minute or less in nitric acid and potassium chlorate. The 



FIG. 64. FIG. 65. 



Fig. 64. Laticiferous tubes from Euphorbia. A, moderately magnified; B. more 

 highly magnified, and showing the bone-shaped or dumb-bell-shapea starch grains. 



Fig. 65. Laticiferous vessels of Scorzonera hispanica. A , a transverse section of 

 the phloe'm of the root ; B, the same more highly magnified. After Sachs. 



fibres may now be separated under a dissecting microscope, or the 

 cases at least, the fibres are not cell-derivatives, and the partitions the 

 persistent walls of the original component cells. 



