42 TRANSACTIONS OF THE [nov. 11, 
study in the medical course. But his fate was to enter and_be- 
come distinguished in a widely different branch which had as 
little attraction for him as for most students of marine life, 
namely, paleontology. He says of this sudden change of base: 
“At last, in 1854, on the translation of my warm friend, 
Edward Forbes, to Edinburgh, Sir Henry de la Beche, the Di- 
rector General of the Geological Survey, offered me the post 
Forbes had vacated of Palzontologist and Lecturer on Natural 
History. I refused the former point-blank, and accepted the 
latter only provisionally, telling Sir Henry that I did not care 
for fossils and that I should give up natural history as soon as 
I could get a physiological post. But I held the office for 
thirty-one years and a large part of my work has been paleonto- 
logical.” 
From this time until 1885 his labors extended over the widest 
field of biology and of philosophy ever covered by any natural- 
ist, with the single exception of Aristotle. In philosophy Hux- 
ley showed rare critical and historical power ; he made the most 
exhaustive study of Hume, but his own philosophical spirit and 
temper was more directly the offspring of Descartes. Some 
subjects he mastered, others he merely touched, but every sub- 
ject which he wrote about he illuminated. Huxley did not dis- 
cover or first define protoplasm, but he made it known to the 
English-speaking world as the physical basis of life—recogniz- 
ing the unity of animal and plant protoplasm. He cleared up 
certain problems among the Protozoa. In 1849 appeared his 
great work upon the oceanic Hydrozoa, and familiarity with 
these forms, doubtless suggested the brilliant comparison of the 
two-layered gastrula to the adult hydrozoa. He threw light 
upon the Tunicata, describing the endostyle as a universal fea- 
ture, but not venturing to raise the Tunicata to a separate order. 
He set in order the cephalopod mollusea, deriving the spiral from 
the straight shelled fossil forms. He contributed to the Arthro- 
poda; his last word upon this group being his charming little 
volume upon the “ Crayfish,” a model of its kind. But think 
of the virgin field which opened up before him among the verte- 
brata, when in 1859 he was the first to perceive the truth of Dar- 
win’s theory of descent. Here were Cuvier’s and Owen’s vast 
researches upon living and extinct forms, a disorderly chaos of 
facts waiting for generalization. Huxley was the man for the 
time. He had already secured a thoroughly philosophical basis 
for his comparative osteology by studying the new embryology 
of Von Baer, which Richard Owen had wholly ignored. In 1858 
his famous Croonian lecture on the “ Theory of the Ver- 
tebrate Skull,” gave the death blow to Owen’s life work upon 
