enough to remember successive generations, cannot fail to 
recognize this fact. 
37. In social science we see that the effect of the causes 
which work among aggregated masses of mankind is usually 
to produce a civilization more or less progressive. But we 
also see, in the daily records of poverty and crime, how' 
civilization itself inevitably leads, in its turn, to degeneracy 
again, unless arrested by stronger motives than nature sup- 
plies, and hence there are natural limits to social progress ; 
limits which many nations, like the Chinese, have long ago 
reached. 
38. Instinct is limited. It is so by the law of heredity on 
which it is founded. Mr. Darwin introduces the conception 
of the variations of instinct becoming fixed into habits, modi- 
fied by external circumstances, and transmitted with all 
improvements. Mr. Spencer has carried this speculation 
further, and has endeavoured to trace a natural growth of 
instinct from a simple reflex action onward into memory. 
But the facts are admittedly wanting to support either of 
these ingenious hypotheses. The observed order of things is, 
that instinct has its barriers as well as its laws. We may 
succeed in instinct, as in form, by the art of training, in 
producing certain alterations or fresh adaptations ; but the 
moment we do so a conflict is set up between the new habit 
and the old tendency, in which the latter ultimately is sure 
to win. 
39. Development is altogether limited by the law of its 
germ. We cannot, therefore, conceive of any essential addi- 
tion, such as intelligence, being added during growth. The 
intellectual functions of man cannot be conceived of as 
growing out of his material structure. 
40. Nor can we conceive of the production of new life by 
any action of matter. The experiments of Dr. Tyndall on 
spontaneous generation, and the researches of others in the 
same direction, forbid the supposition. 
41. Not only do we everywhere encounter limits in nature 
around us, but we find them in the microcosm within us. 
We stretch our mental faculties to the utmost, only to 
meet with the uncognizable. We experience a limit, we are 
at the end of our chain. Professor Tyndall puts this very 
plainly. He says: “Were our minds and senses so ex- 
panded, strengthened, and illuminated as to enable us to 
see and feel the very molecules of the brain ; were we capablo 
of following all their motions, all their groupings, all their 
electric discharges, if such there be, and were we intimately 
acquainted with the corresponding states of thought and 
