NEW CELL FOR^LATIONS IN PLANTS 289 



Lithium Carbonate Injections. 1 :10 Saturated Aqueous Solution 



This series of specimens shows a very prominent stunting of the in- 

 jected internode. Specimens 33, 34, 35. 



Tissue Reactions Following the Injections of Herbaceous Plants 



When the injection was made, two holes were opened in the stem. 

 The liquid, injected thru one hole, ran down the side of the cavity till 

 this was full up to the hole left for the escape of the air. Then the 

 excess fluid escaped thru this hole. The needle was withdrawn, the 

 outside of the stem wiped dry, and a piece of gauze bandage smeared 

 with melted grafting wax was wrapped around the wound. Such 

 were the conditions when the fluid began to act on the stem. Some- 

 times less fluid was injected, and some of the other arrangements were 

 different in the earlier experiments, but the general conditions were 

 the same thruout. 



It will be seen that there were two main regions upon which the sub- 

 stance could act:— the surface of the cavity and the tissues surrounding 

 the vascular bundles which were cut by the introduction of the needle. 

 That these were the only two practicable points of attack was fairly 

 well indicated by the fact that only in these two places, the cavity of 

 the internode and the neighborhood of the vascular bundles, was the 

 Anilin Black seen after injection. To this there is an exception. In 

 the neighborhood of the wound there was a considerable amount of the 

 dye that seeped into the intercellular spaces. This seepage had no 

 effect on the major part of the tissues. The amount of fluid that got 

 into the vessels was much less in the hA-podermic needle injections than 

 in those where the gravity method was used, for in this latter case the 

 number of vessels cut open was far larger. 



The Epidermis. It is now necessary to turn to a detailed considera- 

 tion of the tissue modifications produced by the injections. So far as 

 the material went, there was no evidence of any tissue production from 

 the epidermis, even tho in the young specimens injected the development 

 of a cuticle could not have advanced very far. 



The Cortex. The cortex usually only shows the effect of the injection 

 near the wound. This may either be due to the mechanical irritation 

 or the percolated injection fluid. The extrafascicular bundles will 

 be considered later. 



In spite of the fact that the outer cortex was a well developed collen- 

 chyma, it proliferated freely in Phytolacca, Polygonum and Ricinus. 

 It proliferated in Helianthus also. The product was sometimes an 



