576 JAMES E. ELOMFIELD. 



stretching and thinning from the growth that is taking place 

 beneath it. The sclerenchyma bundles are, however, less 

 numerous and less defined. Beneath the cortex is a layer 

 consisting of bast and cambium, the separation of which is 

 marked in all parts except over the tumour, where no distinc- 

 tion can be made. In the centre of the section is the pith, 

 surrounded on all sides by the wood, the continuity of whose 

 ring is interrupted by the tumour which dips into the wood 

 ring in a wedge-like manner. As a rule it does not reach the 

 pith unless the section has passed near a leaf-shoot, which 

 may happen, because a favourite phice for the young colony 

 is just above a leaf-shoot which serves to shelter and protect it 

 from wind and rain, both of which are very disastrous for the 

 propagation of the species. 



In such a section as I have described all lignified cells are 

 stained pink with the fuchsin, and it is easy to distinguish 

 the soft cellular cells of the tumour from the lignified cells of 

 the wood. If examination is now made with a higher power 

 it will be found that no hard and fast line separates the 

 tumour from the wood, but that the tumour cells seem to 

 arise by alteration of the wood parenchyma cells. Among 

 the tumour cells, however, will be discovered pink-stained, 

 large, irregular cells, which evidently are altered, pitted, and 

 scalariform wood-vessels, enlarged in size, and irregular in 

 shape. These must have arisen from altered cambium cells. 

 The general arrangement of the cells of the tumour is in a 

 radial direction. Large oblong nuclei can be seen in each 

 cell, and in some cases there are several in each cell, a fact 

 which was pointed out by Prillieux. The soft walls of the 

 cells arc composed of cellulose, as shown by Schultz reagent. 

 There is hardly any starch present, as revealed by iodine, 

 but there is sugar in relatively large quantities. If a section 

 is made of a fresh tumour, and tested with Fehling's solution, 

 this fact comes out plainly by the reduction that takes place 

 in the tumour. A rough quantitative estimation showed 

 1 per cent, of sugar in the tumour, while small fragments 

 from the same stem hardly yielded any reaction at all. A 



