and simultaneously represented its most advanced spirit of
speculation. It was followed some years later by a similar treatise, _De
Varietate Rerum_ (1557), the two making in effect but one book. A great
portion of this is occupied by endeavours, commonly futile, to explain
ordinary natural phenomena, but its chief interest for us consists in
the hints and glimpses it affords of principles beyond the full
comprehension of the writer himself, and which the world was then by no
means ready to entertain. The inorganic realm of Nature he asserts to be
animated no less than the organic; all creation is progressive
development; all animals were originally worms; the inferior metals must
be regarded as _conatus naturae_ towards the production of gold. The
indefinite variability of species is implied in the remark that Nature
is seldom content with a single variation from a customary type. The
oviparous habits of birds are explained by their tendency to favour the
perpetuation of the species, precisely in the manner of modern
naturalists. Animals were not created for the use of man, but exist for
their own sakes. The origin of life depends upon cosmic laws, which
Cardan naturally connects with his favourite study of astrology. The
physical divergencies of mankind arise from the effects of climate and
the variety of human circumstances in general. Cardan's views on the
dissimilarity of languages are much more philosophical than usual at his
time; and his treatise altogether, though weak in particular details, is
strong in its pervading sense of the unity and omnipotence of natural
law, which renders it in some degree an adumbration of the course of
science since the author's day. It was attacked by J.C. Scaliger, whom
Cardan refuted without difficulty.

The celebrity which Cardan had acquired led in the same year (1551) to
his journey to Scotland as the medical adviser of Archbishop Hamilton of
St Andrews. The archbishop was supposed to be suffering from
consumption, a complaint which Cardan, under a false impression, as he
frankly admits, had represented himself as competent to cure. He was of
great service to the archbishop, whose complaint proved to be
asthmatical; but the principal interest attaching to his expedition is
derived from his account of the disputes of the medical faculty at
Paris, and of the court of Edward VI. of England. The Parisian doctors
were disturbed by the heresies of Vesalius, who was beginning to
int