90 EXPERIMENTAL PLANT PIIVSKILOGY 



Method. — (a) A gas-j.u- is fitted with a cork. A 

 small groove is cut in the lower end nf the cork, and 

 into this is fixed one end of a strip of slui't ('ork 

 measuring about one inch b}- six. 



Three soaked broad-beans are then pinned on to the 

 piece of cork. The beans arc arranged so that the 

 radicle points, in one case, downwards ; in the second, 

 upwards ; and, in the third case, horizontally. The pins 

 can be stuck through the cotyledons, but care must be 

 taken to prevent their penetrating plumule or radicle. 



A little water is put into the bottom of the jar, but 



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the strip of cork shovUd not dip into it. The jar is 

 then covered with black paper. This is a very simple 

 way of showing the direction of growth taken by the 

 root, but the following method is preferable for demon- 

 strating the direction of growth of the shoot, as it does 

 not necessitate the use oi a closed jar. 



(b) A gas-jar or lamp-chimney is lined with a roll 

 of blotting-paper. The roll is filled up with moist saw- 

 dust or moss so that the blotting-paper may be kept 

 damp. Seeds are then carefully placed between the 

 glass and the paper in the three positions given above. 



