exposed to peculiar difficulties, be regulated by
peculiar laws. Otherwise, the physiologist will
scarcely escape from the imputation of cruelty.
The first principle to be laid down for the
prosecution of physiology is this: we should never
have recourse to experiment, in cases in which
observation can afford us the information required.
The various cases of monstrosity, and the
interesting facts supplied by comparative anatomy,
afford us ample scope for pure observation. They
are a sort of natural experiment. And it appears
to me that, in general, they present to us far
less equivocal phenomena than any which can
result from an actual operation involving the
infliction of violence or of pain.
The physiological argument deducible from the
facts observed in cases of monstrosity, was first
clearly drawn by Mr. Lawrence 1 in this country,
and afterwards by M. Lallemand 2 in France. The
subject deserves still further attention, and will
be repeatedly noticed in the following pages.
1 Medico-Chirurgical Transactions, Vol. v. pp. 164—224. June,
1814.
2 Observations Pathologiques ; par E. Lallemand. Thèse soutenue
le 6 Août, 1818.
M. Geoffrey-Saint-Hilaire1 has beautifully pour-
trayed the anatomy of monstrosity. It still
remains to elucidate its physiology in the same
complete and philosophical manner.
It may be remarked also that comparative
physiology has not kept pace with comparative
anatomy. But the subject appears at present to
be obtaining due attention. It will be seen in
the course of this little work, how indispensable
the knowledge of comparative anatomy is to the
physiologist.
In addition to the sources of physiological discovery
afforded by cases of monstrosity and by
comparative anatomy, the various results of disease
and of accidents afford us examples of undesigned
experiments. M. Lallemand appears to me to
have availed himself of these circumstances, as a
physiologist,2 more completely than any other
observer. And here the eloquent expression of
Celsus may be not inaptly quoted : “ quæ cognosci
in vivis possunt, in ipsis curationibus vulnerato-
rum, paullô tardiùs, sed aliquanto mitiùs, usus
ipse monstrabit.” 3
> Des Monstruosités Humaines.
2 Observations Pathologiques. 3 Præf. sub finem.
B 2