December 3, 1915] 



SCIENCE 



785 



known to us, but it is regarded as a subject 

 for scientific inquiry and further explana- 

 tion. To recognize fully the complexity of 

 the substance of the plant is not, however, 

 a step towards neo-vitalism, but is perhaps 

 our best safeguard against the dangers of 

 this. 



The wholeness of the individual, together 

 with important phenomena of regeneration, 

 has suggested the conclusion that something 

 other than physico-chemical or mechanical 

 laws are concerned in the development of 

 the organism. To this something Driesch 

 applies the name entelechy. Without dis- 

 cussing the vitalistic philosophy of the 

 organism, or other modern phases of philo- 

 sophic thought that treat life as an entity, 

 it seems worth while to point out that they 

 are based mainly on the consideration of 

 animal development. It would be interest- 

 ing to inquire into the difficulties that are 

 met with in applying such views to plants, 

 where regeneration in one form or another 

 is the rule rather than the exception, and 

 often does not lead to restitution of the 

 individual. Causal morphology can recog- 

 nize phenomena of development and of the 

 individual, which are at present beyond 

 physico-chemical explanation, and try to 

 attack them by any methods of investiga- 

 tion that seem practicable, without beg- 

 ging the main question at the outset and 

 then proceeding deductively. To assume 

 any special inner director of development, 

 be it entelechy or vital force, is to cut the 

 knot that may ultimately be untied. 



The previous experience of botany in the 

 time of nature-philosophy may well make 

 us cautious of solving our difficulties by the 

 help of any new biological philosophy. On 

 the other hand, cooperation between biology 

 and philosophic thought is highly desirable. 

 In this connection I should like to refer 

 to an idea contained in Prof. Alexander's 

 paper on the basis of realism. He suggests 



that there is only one matrix from which all 

 qualities arise, and that (without introduc- 

 ing any fresh stuff of existence) the second- 

 ary qualities, life, and at a still higher level, 

 mind, emerge by some grouping of the ele- 

 ments within the matrix. The development 

 of this idea as it applies to life would ap- 

 pear to offer a real point of contact between 

 inductive biological work and philosophy. 



To return to our plant, its development, 

 with increase in size and progressive com- 

 plexity of external form and internal struc- 

 ture, must be considered. The power of 

 continued development possessed by most 

 plants and wanting in most animals makes 

 comparison between the two kingdoms diffi- 

 cult. That there is no fundamental differ- 

 ence between the continued and the defi- 

 nitely limited types of embryogeny is, how- 

 ever, shown by plants themselves. The 

 bryophyte sporogonium is a clear example 

 of the latter, while the fern sporophyte is 

 one of many examples of the former. A 

 difference less commonly emphasized is that 

 in the sporogonium (as in the higher ani- 

 mals) the later stages of development pro- 

 ceed by transformation of the whole of 

 the embryo into the mature or adult condi- 

 tion ; in the fern-plant the apical develop- 

 ment results in successive additions of 

 regions which then attain their mature 

 structure by transformation of the meriste- 

 matie tissue. 



These distinctions are of some importance 

 in considering the generalization originally 

 founded on animal development and known 

 as the biogenetic law. That "the ontogeny 

 is a concise and compressed recapitulation 

 of the phylogeny" is essentially a phyletie 

 conception. It has been more or less criti- 

 cized and challenged by some distinguished 

 zoologists, and has always been difficult to 

 apply to plants. If we avoid being pre- 

 judiced by zoological theory and results, we 

 do not find that the characters of the em- 



