100 BLOOM. [CH. IV 



or some other succulent plant with a good bloom. It 

 is best to bring the pot into the laboratory because 

 if the leaves are cut before they are wanted they are 

 likely to get rubbed. Cut off two similar leaves (or two 

 similar twigs) and pierce each specimen with a piece of thin 

 copper wire to serve as a hook by which to hang it up. 

 Paint the cut surfaces with lard: weigh the specimens, 

 hang them in a dry room for 12 or 24 hours, and weigh 

 them again. This will give the normal transpiration of 

 the two specimens. Now remove the bloom from one 

 specimen by delicate sponging with water at 35° C. When 

 it is dry weigh both again, and once more expose them 

 to the dry air of the laboratory for 12 or 24 hours. The 

 cleaned specimen should now transpire relatively more 

 than the other. 



