THE AMERICAN NATURALIST 



[Vol. XLII 



sufficient to explain the inheritance of the character. It 

 is necessary to assume a corresponding and very definite 

 change in the bearers of the hereditary characters. Just 

 how these bearers are constituted or what name is given 

 them is entirely immaterial. It is probable that they are 

 of an exceedingly complex nature. For purposes of illus- 

 tration they may well be compared with the molecules of 

 organic chemistry, or better still, as has already been 

 done so felicitously, to many-sided prisms, which a very 

 slight jar causes to assume a different position and which 

 finds a corresponding external expression. Under pre- 

 disposition to fasciation or the latency of the fasciated 

 character should perhaps be understood a tendency on 

 the part of the cell contents, and more particularly the 

 chromatin, to undergo a certain definite change, retained 

 during cell division, of either a chemical or physical 

 nature, under certain conditions brought about by differ- 

 ences in nutrition. The change which causes fasciation is 

 one of the easiest brought about, and hence fasciation is 

 one of the abnormal characters most frequently met with. 

 Though a mere theory, its general truth is supported by a 

 number of instances. Mutations frequently repeat them- 

 selves. The identical sports originating from stock ob- 

 tained from widely different sources and where the proba 

 bility of a common origin in the remote past may safely 

 be questioned, speak for themselves. The finding in two 

 distinct places in Europe of plants of Capsella heegeri 

 Solms, which differs from C. bursa-pastoris mainly in the 

 shape of its capsules, is another instance. Mutations in 

 a species are always the same, whatever their direction. 

 They may be widely separated in time and space, but 

 whenever they appear they arc identical. 



It has been said that fasciations are inherited because 

 the seeds collected for purposes of propagation always 

 were obtained from the abnormal stems. This appears 

 to have happened in the majority of cases. Since, how- 

 ever, we never can know whether a fasciation is inherited 



