120 PRACTICAL BOTANY 



will be found that they originate from a number of originally 

 separate cells of the cambium, the cavities of which are thrown 

 together by the partial or complete absorption of the walls. Such 

 fusions may appear in the terminal or the lateral walls. 



Note on Timlin. 



From a fresh tuber of the Jerusalem Artichoke (Helianihus 

 tiiberosus), or from fresh Dandelion roots cut sections in any 

 direction, and mount them in a very small quantity of water : 

 examine under a low power, and observe that the tissue is chiefly 

 composed of cells with transparent contents. 



Irrigate the sections well with alcohol : a granular precipitate 

 will appear in the fluid surrounding the sections, and a similar 

 precipitate will also be seen within the cells, which may be so 

 bulky as to make the whole section appear opaque. 



Now irrigate thoroughly with water : the precipitate will again 

 dissolve. 



Cut sections from material which has been kept for some weeks, 

 or better for some months, in alcohol : mount in glycerine, and 

 observe the transparent tissue as before : here and there will be 

 seen large circular patches of highly refractive substance, which 

 are of such size and position as often to extend over a number of 

 cells : these are the sphere-crystals of inulin, 



Treat with iodine solution : they are not appreciably coloured. 

 Irrigate well with water : they are slowly dissolved, their solu- 

 tion being hastened by warming, and they show a radiate 

 structure as solution progresses. Treat with potash : they are 

 dissolved more quickly, without any coloration. 



A similar substance, hesperidin, is found in young Oranges : 

 if these be treated for a long time with alcohol, the tissues will be 

 found crowded with sphere-crystals, which have similar reactions 

 to those of inulin, but on dissolving in potash the solution takes 

 a yellow colour. 



ii. Laticiferous Cells. 



I. Cut tangential sections of the cortex of Euphorbia 

 splendens (other species will do) just outside the vascular 



