Spencer 227 
into the organism by the new function, nor consequently 
with any new physical or chemical or biological character 
which the organism has now for the first time acquired; 
but on the contrary there is involved only a different dis- 
tribution of already existing qualities of matter. But 
how can a change of quality in imaginary physiological 
units, which would have proceeded uniformly in the 
whole organism, accord with the fact that all the qualities 
and properties of this organism remain unaltered, and 
there is merely another distribution of these materials? 
Let us consider as a further example the instinct of 
ew born chickens. ‘In the first minutes of life,” writes 
Jastrow, “chickens follow with their eyes the movements 
of crawling insects, turning their heads with the precision 
of an old fowl. In from two to fifteen minutes they 
pecked at some speck or insect, showing not merely an 
instinctive perception of distance but an original ability 
to judge, to measure distance with something like in- 
fallible accuracy. A chicken hooded as it emerged from 
the shell was unhooded when three days old; six minutes 
later it followed with its head and eyes the movements of 
a fly twelve inches distant, and about ten minutes later 
made a vigorous dart at the fly, seized and swallowed it 
at the first stroke.” 174 
Spencer would rightly attribute this instinct to the 
long practice acquired by the ancestors of the chicken. 
But if he wished to explain this inheritance through the 
alteration of specific physiological units of the entire 
organism, such an explanation would not be taken ser- 
iously. How could the new physiologic units, capable 
of effecting this local modification constituted by the 
™3Tastrow: The Problems of Comparative Psychology. The 
Popular Science Monthly. New-York. Nov. 1892. P. 36—37. 
