PART II. 



ATROPHY. 



Under the head of atrophy are included those cases 

 wherein the organs affected are actually present, but 

 in a dwarfed and stunted condition as compared with 

 surrounding parts. 



The diminished size is, in such instances, obviously 

 due to a partial development and to an arrest of growth 

 at a certain stage, from the operation of various causes, 

 either external or inherent to the organization itself. 

 It may affect any part of the plant, and exists, in very 

 varying degree, in different instances, being sometimes 

 so slight in amount as not to preclude the exercise of 

 the functions of the part ; while in others, the struc- 

 ture is so incomplete that the office cannot be per- 

 formed. These differences depend, of course, upon 

 the stage of development which the organ had reached 

 when its growth was checked. For practical pur- 

 poses atrophy may be distinguished from suppression 

 by the fact that in the latter case a certain element 

 of the flower or plant which, under ordinary circum- 

 stances, is present, is entirely wanting, while, in the 

 former class, it exists but in a rudimentary condition. 



Again, atrophy is to be separated from that geileral 

 diminution in the size of the whole plant or of distinct 

 parts of that plant which is comprised under the term 

 " nanism." Thus the several dwarf varieties of plants 

 (yar. nmuc), or those in which the leaves or flowers are 

 smalk^r than usual (var. parvifolicPi v. parviflorce)^ are 

 truly regarded as variations, and not as malformations 

 properly so calletl. 



