212 life
animal kingdom:Radiata, Articulata, Mollusca, and Vertebrata. Addressing Dar-
win, Lesley pointed out the resulting difficulties:
My dear sir, you have four times as much to do as you thought you
had. You must not only explain how a man came from a monkey,
and a monkey from a squirrel, and a squirrel from a bat, and a bat
from a bird, and a bird from a lizard, and a lizard from a fish; but
you must suggest some possible means of transforming a vertebrate
fish out of a shell fish, or out of a jelly fish, or out of a lobworm or
trilobite; then you must go on to show us how the first trilobite, or
the first coral animal, or the first shizopod was obtained by your
process of natural selection out of still earliervegetablespecies. Nay,
you cannot even stop there. You must explain the very first appear-
ance of living tissue out of the inorganic elements of dead matter.Darwinism, he concluded, remained “an open question...that ought to be no
bugbear in the path of generous and truthful minds.”^23
Many early Darwinists, such as the Harvard botanist Asa Gray, accepted
organic evolution in general but made a special exception for humans. Lesley—
uniquely, as far as I can tell—rejected what has come to be called macroevo-
lution, but argued that humans had descended from apes. With Darwin, Lesley
believed “that man is a developed monkey,” but instead of one evolutionary
track for humans he argued for three: each descending from a different type
of “manlike ape, viz. the orang, the chimpanzee, and the gorilla, the three
principal divisions of the family of apes.” The only barrier to accepting such a
human history, he maintained, was the “tissue of absurdity, called the biblical
history of the origin of mankind.” No wonder he reported to his wife following
this lecture: “You can’t imagine what amusement my flat-footed advocacy of
the monkey origin of man occasioned. There was no end to the jokes.”^24
Despite “threatening symptoms and occasional illness,” Lesley had main-
tained a heavy work load. But shortly after completing his Lowell lectures, he
suffered from what a nephew described as a “completely broken down” ner-
vous system, or what we would call severe depression. According to an intimate
friend, a “black cloud of cerebral exhaustion” came over him, and his “brain-
battery” ceased to function. A couple of years recuperating in Europe helped,
but more years passed before he could put in a full day of work.^25 In 1872, the
University of Pennsylvania appointed him professor of geology and mining
and dean of the “Scientific Department.” Two years later he replaced Rogers
as the state geologist of Pennsylvania. In the early 1890s, his incapacitating
depression returned, and this time he never recovered. It is unlikely that we
will ever know what role religious and scientific doubts played in his repeated
breakdowns, though indirect evidence suggests that they were not insignifi-
cant.^26
Although Lesley occasionally attended a Unitarian church with his family,