454 PROCEEDINGS OF THE ACADEMY OF [July, 



with those of the adjoining sphere-crystals. The latter arrange- 

 ment may be likened to the pores in such thickened cell-walls. 



A resemblance to the wav}' contour of the walls of transverse 

 sections of epidermal cells is exhibited in the residue formed by 

 the evaporation of bruciue solutions. 



The iufoldiugs in the parenchyma cells in piue stems and leaves 

 is exemplified in the arrangement of the crystals which result from 

 the evaporation of solutions of amygdalin. 



From solutions of caffeine hydrobromate there separate crystals 

 which in abundance and in arrangement resemble a dense mycelial 

 development of penicillium with conidia. 



The crystalline residue from solutions of berberine shows a 

 marked resemblance to the outer morphology of certain Lycopc- 

 diums, species of Juniper and other similar arborescent plants. 

 Illustrations of this kind could be multiphed Avhich would lend to 

 show a relationship between the form of crystalline groups and 

 the ultimate arraugetnent of the substances entering into the com- 

 position of the plant. 



The chemist has considered but one phase of the subject of 

 crystallization, namely, the form and nature of individual crystals. 

 The botanist, however, until recently has considered the aggre- 

 gation of morphological units, as is evidenced in his studies od the 

 outer and inner morphology of plants. But as the form and 

 nature of the individual units are seen to depend more or less upon 

 the nature of the substances comprising them, it becomes of fun- 

 damental importance to study the composition of these units in 

 their relation to form and structure. 



In the case of inorganic bodies chemical as well as physical tests 

 are necessary to prove the identity of a substance. In the organ- 

 ized, or organic, world it has been impossible to define a si^ecies or 

 designate the limitations of a species because our studies have been 

 directed almost entirely to the outer morphology of individuals , 

 rather than to the study of the substances which, grouped 

 together, form these individuals and the physical and chemical 

 forces underlying their structural arrangements. 



The same substance may under different conditions develop 

 different outer forms, as, for example, alum may crystallize in 

 monoclinic prisms, hexagonal prisms, or in arborescent forms or 



