SEOOOT) REPORT ON YAEIOTTS MANURES AT CHISWICK. 157 
any change in the plant of a kind that a naturalist would deem of 
" specific " value could be artificially induced. 
All that the manures did in this direction was to enhance the 
vigour of growth or the reverse. The eff'ect on the vegetative 
system (leaves, stem, &c.) was in all cases more pronounced and 
decided than it was on the flowers and seeds. 
That greater changes might have been induced by careful selec- 
tion is of course not open to doubt ; but that is not the point with 
which we are here concerned. 
It would seem from this, as indeed all evidence we have yet 
obtained shows, that " specific " characters are not influenced by 
external conditions, at any rate within short periods of time. 
The specific character is an innate quality transmitted by heredi- 
tary descent, and not materially altered by changes in external 
conditions. This was exemplified by the circumstance that in 
the case of the Plantain (Flantago lanceolata), numerous self- 
sown seedlings appeared in all the experimental boxes (five 
treated with as many diflerent manures, one unmanured), and 
among these seedlings were many variations in shape and colour 
of leaf, pubescence, &c., variations which could not be attributed 
to the immediate operation of external conditions, seeing that they 
appeared in all the boxes indifferently, and in each box under the 
same conditions. 
The physiological characters, however, as we have seen, are 
materially influenced by these agencies ; and it is quite conceiv- 
able that in course of time they might determine specific changes. 
These may seem large inferences to be drawn from such premises 
as are afforded by the Chiswick experiments ; but the reader must 
judge of their value for himself; and he will recollect that few 
experiments of this character and magnitude have hitherto been 
made, and few opportunities afforded for examining for so consider- 
able a period so large a number of different plants, and grown 
under more than usually definite conditions. The magnificent 
and far more important series of similar experiments carried on 
for so many years at Eothamsted and at G-iessen are not fairly 
comparable with the Chiswick trials, as the objects and conditions 
were both different. Moreover the opinions here expressed tally 
with those of most who have written on the subject. 
In reference to the main objects for which these experiments 
were carried on, the following considerations also seem to claim 
attention. They are not novel ; but, from that very circumstance, 
