310 
bryological subjects and from the labora- 
tory announcements of Harvard, Johns 
Hopkins and many other centers for inves- 
tigation and sound embryological instruc- 
tion. 
It was intimated above that the pressing 
need of zoology to-day is complete knowl- 
edge of some typical forms, such, for ex- 
ample, as are represented by the domestic 
animals in the avian and mammalian 
classes. This thorough knowledge is 
needed rather than more of the bits and 
patches from the entire animal kingdom. 
It is certainly true that morphological 
knowledge at the present day is too much 
like a crazy quilt. This every investigator 
finds to his cost when he wishes to carry a re- 
search beyond the most elementary stages. 
What is needed, then, is concentration— 
complete knowledge, so far as possible, of 
each form investigated ; and this knowl- 
edge must compass the entire life cycle. 
As also stated above, embryology has, and 
perhaps properly, concerned itself largely 
with the beginnings of the organisms and 
their organs. But in so doing the later 
but no less important changes have been 
left almost untouched. Ontogenetic de- 
velopment after birth is of the profoundest 
importance from all biological standpoints. 
In some ways a knowledge of how the new- 
born becomes an adult is certainly of pro- 
founder interest than how an egg becomes 
a new-born animal. A few years ago the 
agricultural experiment stations, especially 
those of Wisconsin and New York, wished 
to answer, so far as possible, the question of 
how to obtain the best nutrition and growth 
to render animals most satisfactory as food 
and thus, also, the most profitable in the 
market. 
There arose questions concerning the 
changes in muscle, if any, in passing from 
youth to maturity and from maturity to 
old age; from a condition of leanness to 
fatness. Here were some very pertinent 
SCIENCE. 
[N.S. Vou. X. No. 245. 
questions which only a biologist could an- 
swer, but at that time many of the ques- 
tions were enshrouded in darkness. But 
during the present year several investiga- 
tions bearing upon these points have been 
published. Every one knows that the 
muscles increase in size as well as in 
strength in a growing animal, and also that 
they increase in size and strength in an 
adult if properly exercised. But who 
would have been prepared to expect that in 
this increase in power and size of the whole 
muscle the individual fibers of which it is. 
composed would actually decrease in num- 
ber? This brings us to the fundamental 
question of the mechanism and the struc- 
tural changes by which youth and maturity 
are merged into old age and decay? If 
you will read the suggestive address of Dr. 
Minot given at the Indianapolis meeting in 
1890, and the papers of Hodge on the 
changes in nerve cells from childhood to 
senility, you will gain a notion of the work 
to be done upon the post-embryonal ontog- 
eny, and the rewards to be gained by the 
faithful, clear-brained investigator. 
I cannot leave this part of the subject 
without reminding you again of the brill- 
iant part the paleontology of the horse 
has played in zoological science, and to ex- 
press the belief that its embryology, when 
thoroughly worked out, will play an equally 
brilliant one. At present this embryology 
is known only in fragments. Why should 
there not arise in this boundless western 
world, in the land where the earliest horses. 
appeared, some embryologist who, with 
the cheap and abundant material, should 
work out this problem with completeness ? 
Next to man himself there is probably no 
animal in which the civilized world is more 
profoundly interested. To trace in the 
growing embryo not only its own life his- 
tory, but to gather as many and clear 
glimpses as possible of its race history, 
would, indeed, be an inspiration. -Enough 
