ACADEMY OF SCIENCES. 101 
progenitors and all others. The fittest will maintain itself and the others 
perish, the parent and derived forms being equally dependent upon their indi- 
vidual adaptability to surrounding conditions. Thus, certain localities still 
exist in the condition of ages long past, where inferior races yet flourish and 
find themselves better off, more competent to deal with difficulties in their 
way, than any variation derived from their type. While conditions continue 
unchanged they remain unsupplanted by other forms, and their type becomes 
very pronounced. Exact reproductions are rare. Amid infinite similitude 
there is infinite diversity; and imperfection is a vast fact, which must always 
be taken into account in all hypotheses. ‘‘ Animal beauty arises from the 
perfect balance of physical parts and the rhythm and perfection of their 
action.’ It is probable that no perceptible change has taken place in the 
Chinese race for many years, because in that time the incomplete changes of 
physical condition in their country have not admitted of it. Wheat found in 
tombs with Egyptian mummies, when brought from darkness into sunlight 
and planted in congenial soil, grew and produced wonderfully, but could 
never have developed without a change of conditions. Change is imperative 
to progress. 
A complete knowledge of embryology furnishes an unerring record of the 
origin and development of any form of animal life; for the embryo of higher 
types, while in process of maturing, pass successively through a recapitula- 
tion of all forms by which their species ascended by evolution to their present 
condition. Since conception, each human being has passed rapidly through 
modifications, the counterpart of the graduated forms through which his race 
has been slowly built up, and his present condition reached. Thus, we have 
a history of human evolution republished in every case of reproduction. 
Man, as traced by his embryotic development, commenced, when in dark- 
ness, the cohesion of two or more gelatinous molecules, impelled by a con- 
stantly-progressive life-principle, united to form a microscopic zodsperm, 
capable of preserving its new condition in a thick and heated liquid. The 
proportionate duration of early life in warm water is revealed by the first nine 
months of his existence, during which many successive but correlated forms 
are assumed. Dr. Cohnstein, of Berlin, (quoted in the Lancet, May, 
1875,) ‘‘has determined by means of the thermometer that the temperature 
proper to the fetus in utero is higher than that of the mother.’’ The hot salt 
sea in which early life developed, is here typified. The period of atmos- 
pheric air having arrived at birth, emerging into light, his aquatic life ends, 
and becomes terrestrial and aérial. New elements of food are supplied, and 
the mode of nutrition changed. For awhile his food continues liquid, and 
he sees, hears, and notices but little. By degrees he arrives at a conscious- 
ness of the solid world, first rolling, then creeping, seal-like on four 
limbs, then sits upon his haunches, and finally walks erect, at first trem- 
blingly, then playfully, but firmly, at last. This reveals how nature required 
successive physical conditions, to acquire progressive results. Each being 
owes his present bodily form, to ascent through a parentage, each change 
of which has passed away, after accomplishing its intended purpose, a cul- 
mination reached by degrees, through countless generations of improvement® 
In due time, children acquire teeth, and another change of food ensues, 
