SEPTEMBER 8, 1899. ] 
with the profession of human medicine ; 
and that human medicine in turn should 
reap even greater good in future by a more 
thorough appreciation and study of com- 
parative medicine ?* 
At this time, when the dawn of the 
20th century is already in the sky, the bio- 
logical problem most important to the ani- 
mals, and to the human race in its aspira- 
tions, is the problem of heredity. What is 
its mechanism, what light does it throw 
upon the chances for preservation from 
degradation, and for elevation to exalted 
manhood? Organic evolution has shown 
in the clearest manner that ‘descent with 
modification,’ in order to meet the require- 
ments of the environment, does not, by any 
means, signify in all cases what is com- 
monly meant by the term progress. Con- 
sider the mental and physical condition of 
parasites. They have descended literally, 
and with the profoundest modifications. 
Look at the serpents and the partly limb- 
less forms of the ocean. In their descent 
they progressed toward fitness for their 
environment, fitness to make the most and 
best of the life they have to lead ; but this is 
not the modification desired in human de- 
scent. The Utopia for human society is 
where there is abundant food for all, con- 
genial labor for all, education and amuse- 
ment for all, every one to work out in its 
fullness his own individuality and at the 
same time serve the common weal. What 
lessons do the domestic animals give upon 
this? That ‘like produces like’ is a gen- 
eralization believed in by every one, and 
sufficiently supported by every-day obser- 
vation. Equally true and general is the 
* For further discussion of the relations between 
human and comparative medicine, see for Compara- 
tive Medicine, Dr. James Law’s address atthe inau- 
guration of the New York State Veterinary College, 
September 24, 1896.— Veterinary Magazine, September, 
1896. For Human Medicine, see Dr. Charles S. 
Minot’s Yale University Medical Commencement Ad- 
dress, June 29, 1899.—ScIENCE, July 7, 1899. 
SCIENCE. 313 
statement that ‘ like produces unlike ’—that 
is, no offspring is exactly like its parents, 
and no two offspring are exact duplicates. 
While the race type is persistent, individual 
modifications are infinite. In this likeness. 
and still unlikeness between offspring and 
parent is the hope and the despair of man- 
kind. The hope because every horticul- 
turist, every stock breeder and every parent 
hopes that the offspring will be unlike, but 
that the unlikeness will be an improvement. 
The despair because unlikeness is just as 
liable to take the trend of the undesirable 
qualities and intensify them. With the 
lower animals the undesirable modifications 
may be eliminated, must be eliminated, or 
the race will deteriorate. In the human 
family the problem is equally plain, but in- 
finitely more difficult of execution. How 
can the brood of criminals be avoided and 
the sturdy and right-minded possess the 
earth ? 
If one would see how social theories have 
worked themselves out successfully the 
domestic animals again furnish models, 
models in which theory is no longer theory, 
but fact under which thousands of genera- 
tions have lived, flourished and passed 
away. ‘The most perfect states are found 
among the social insects, foremost of which 
are to be mentioned the honey-bee. This 
society, which man has had under domesti- 
cation so many thousand years that the 
beginning has been forgotten, has won the 
admiration of the world, and poets and 
philosophers have immortalized it with their 
words. What could appear more perfect ? 
Each member of the society is apparently 
free, and each labors for the common good. 
Truly it seems an ideal state, but to attain 
this ideal state queens must kill their 
sisters or be killed by them; thousands 
must be relegated to ceaseless toil, and 
kings exist but for a day. This perfect 
state consists only of a queen-mother and 
thousands of sexless slaves. All exist, not 
