New-York tribune., 1903-03-01


nnity. Thus, find in the less specialized meme
hers of the primates. such the 1emurs and the
oldest true monkeys. the relative development OF
the cerebral heispheres to be little If any. greater
than that Of many Of the insectivora, now repre-
sented by nnoIes. hedgehogs ETC.; and were COM
PEELED depend this character alone it would
in many instances be impossible 20 determine
whether the animal in question was an insectVore
monkey.
'Recognizing the importance of thus clearly dis
tinguishing between the small Drained prinnates
and other contiguous groups. 1 have been LED 10
make careful study of the manner in which the
blood supply Is furnished the cerebral hemispheres
on the assumption that 1t must have been not only
intimately associated With the progressive enlarge
rnent Of the cerebral hemispheres, but was In way
not clearly understood IN some oesree at 4@dS'
responsible for it,
Coming to the discussion, therefore, of the rea-
sons for this advantage which the monkey pos
sessed in blood supply to the brain. Dr. workman
enters length in his paper into close stuOy ch
the cerebral ctrcV1stioE, winch may De eulAAiI@i
tzed follows:
The arrangement Of the entocarodd circuieuon'
or direct blood supply is different in monkeys apes
and nan from that OF the lemurs. In one group
of the Ienurs the blood through the entocarottd'
or main artery Is carried directly to the base OF
the skull. where the artery enters the MIDDLE or
cerebral chamber. In another group the blood Is
delivered into the posterior chamber OF the SKULL
through an opening alongside the pouch In
monkeys and man the entocarotid pierces the ear
cha nber delivers the blood directly to the base
of the brain in the middle chamber. As far as di-
rectness OF supply goes the arrangement found In
one section OF the Ien1urs appears to be as ad-
yautaEecus as that Of monkeys and man. Upon
any hypothesis which involves this blood supply
through the cntocarotids the brain OF these forms
of lemurs should have developed as rapidly as those
OF the monkeys. The explanation Of this seeming
inconsistency lies in the relative Importance OF
the two sets of arterial feeders of the cerebral
heEnispheres the entccarotid and the Ferteorats.
In monkeys and man the vertebral branches are
Enato o.HAa mt md
csrotidS correspondingIy large In the lemurs this
condition is reversed. the verteorals being large
and the entccarotids small In the one case the
entocarotids became the predominant feeders OF
the cerebral hemisphere, and there was corre-
snonding increase in size and general increase in
intelligence In the other this oice was performed
largely by veTtebrals. and the brain developed
more slowly. II Is evident that the advantage lay
With the more direct current of blood which must
have resulted in giving a greater stimulus to the
psychic activities Of the monkey and have been
responsible for his evolution in this direction"
Dr. Workman continues:
The modification OF the monkeys hands or feet
into more or less perfect prehensile or graspins,
organs is the second marked feature Distinguishing
the prtates The which led 20 this are little
known but there can hardly be any doubt that 1t
was one OF the primary distinguishing features OF
the remote ancestors Of the monkeys known 70
science as the Metatherians, and placed far back
in the MesoEoc age. The appearance of this char
acterfstic unquestionabIy constituted one OF the
entiation Of the monkey family into such distinct
group
The particular type of extremity from which the
prehensIIe notifications arose was undoubtedly
that Of the plain pIantigrade, or natfooted. cond
tion and the assumption Of an 2rbereal manner 9f
Hfe we may believe, was the all important deter
mining factor in this evolution.
Exclusive of man. the prinates without e1-
ception the most pre-eminently arooreaI OF naoit
Of all the mammals. The opposabiIity Of the great
toe and thumb or the ability TO place them op-
posIte the other toes fingers. is Of vast su-
periortty to claws When the large branches OF the
adjoining trees intsrlace, the clawed animal eS-
periences little dsculty In passing from one to the
other But IL the trees scattering SO that only
the small branches touch, his progress ts barred
To the antnsl with prehensle extremides, how
ever. the case is different He simply runs out
until he can gather handful Of tWigs or smaller
branches of the opposite tree. and Swings himself
across the Intervals with ease
..It is Of course impossible discover just what
comblnatIon Of circumstances nrst led the ancestors
Of the prtnnates to adopt arboreal habit II may
have been for the purpose Of greater protection from
enemies; IT may have been that certain kinds OF
food such fruit and nuts. attracted them to the
trees; IL may have been both. But. whatever the
cause IL appears certain that this manner OF HE
was adopted very early In their career, and has
been responsible for one OF the most important
structural notifications which they now exhibit
"A matter OF great interest IN connection VILE
the prahense extremities relates to their probapS
influence upon the growth of the cerebral heEni-
spheres, as well the general increase in tntslu~
Kence In the priuates. No history of the existing
species of mo 1keys has yet been made, Dut II Is
clear that the brain has increased IN SIZE over
and above that found in the eGyiieF forms. In the
Ietnurs this has been small In the apes and mon
keys relatively large
Nov. what causes In 1t possible to attribute
this development Of the monkey brain! few
modern naturaHsts claim internal or perfeeting.
principle by which variations are originated or pre-
served and which, Through subsequent action Of
natural selection. forever holds them steaofast IN
the narrow line of their hnaI development must
exprexa nay utter disbelief IN any such view OF
EVOLUTION In my Judgment IN there not only no
STisenfe n. auuSorf ef such proposition but. on
fhs c0ntssFy, an the facts Of psleootoIcgy g tAs