ON THE RELATIONS OF MAN WITH TII[E LOWER ANIMALS 473 
are largely, or wholly, based on the results of experiments on animals, 
The poison which hurts them does not leave us unscathed ; and we share 
with them two of the most terrible diseases with which mortal beings 
are afflicted, glanders and hydrophobia. Nor can any impartial judge 
doubt that the roots, as it were, of those great faculties which confer on 
man his immeasurable superiority above all other animate things, are 
traceable far down into the animal world. The dog, the cat, and the 
parrot return love for our love, and hatred for our hatred. They are 
capable of shame and of sorrow; and though they may have no logic 
nor conscious ratiocination, no one who has watched their ways can 
doubt that they possess that power of rational cerebration which 
evolves reasonable acts from the premises furnished by the senses—a 
process, be it observed, which takes fully as large a share as conscious 
reason in human activity. There is a unity in psychical as in physical 
plan among animated beings ; and the sense of this unity has. been 
expressed in such strong terms by Professor Owen, that his words 
may form a fitting climax to these introductory sentences. 
“Not being able to appreciate or conceive of the distinction be- 
tween the psychical phenomena of a chimpanzee and of a Boschisman, 
or of an Aztec, with arrested brain-growth, as being of a nature so 
essential as to preclude a comparison between them, or as being other 
than a difference of degree, I cannot shut my eyes to the significance 
of that all-pervading similitude of structure—every tooth, every bone, 
strictly homologous—which makes the determination of the difference 
between Homo and Pithecus the anatomist’s difficulty.” 4 
That there are a great number of points of similarity between our- 
selves and the lower animals, then, appears to be clearly admitted on 
all hands. Itis, further universally allowed that the Vertebrata resemble 
man more nearly than do any invertebrates ; that among vertebrates the 
Mammalia, and of these the Quadrumana, approach him most closely. 
Lastly, I am aware of no dissentient voice to the proposition, that in 
the whole, the genera Troglodytes, Pithecus, and Hylobates, make the 
closest approximation to the human structure. 
The approximation is admitted unanimously ; but unanimity ceases 
the moment one asks what is the value of that approximation, if 
expressed in the terms by which the relations of the lower animals 
one to another are signified. Linnzus was content to rank man and 
1 Prof. Owen on the Characters, &c., of the Class Mammalia, ‘‘ Journal of the Pro- 
ceedings of the Linnawan Society of London,” vol. ii, No. 5, 1857, p. 20, note. It is to 
be regretted that this note is omitted in the ‘‘ Essay on the Classification of the Mamma- 
lia,” which is otherwise nearly a reprint of this paper. I cannot go so far, however, as 
to say, with Prof. Owen, that the determination of the difference between Homo and 
Pithecus is the ‘anatomist’s difficulty.’ 
