362 Analysis of Scientific Books. 
colchicum, now in their glory, are probably destined to share 
the same fate. 
In observing upon the influence of false theories and absurd 
conceits upon the progress of the Materia Medica, our author 
takes a cursory view of some of the principal hypotheses which 
have prevailed in medicine, and which have conferred an ephe- 
meral popularity upon crowds of inert and insignificant drugs. 
The school of Galen, for instance, taught that all medicines 
possessed one of the cardinal virtues of heat, cold, moisture, or 
dryness: diseases were similarly subdivided, and were to be 
treated by the opposite remedies. ‘The four greater, and four 
less, hot and cold seeds, are upon this principle still maintained 
in some foreign Pharmacopeiz ; and in the London Dispensatory 
of 1721, we find the powders of hot and cold precious stones, 
and the hot and cold compound powder of pearls. 
The methodic sect, founded by Themison, referred diseases to 
overbracing, and to relaxation, and adopted a corresponding 
classification of remedies; a theory long banished from the 
schools, but still exerting its influence in practice. They ob- 
served that parchment was alternately rendered flabby and 
crisp by hot and cold water, and thence the notion of the relax- 
ing and strengthening influence of the hot and cold bath upon 
the living fibre. 
The Stahlians, trusting to the Spiritus Archeus, or Vis Medi- 
catrix nature, put but little faith in any extraneous remedies, 
but they were vigilant and acute observers of the progress of 
disease. The Mechanical Theory ascribed diseases to lentor 
and viscidity of the blood; hence the doctrines of obstructions, 
with their corresponding classes of remedies; while the Chemists, 
on the other hand, explained all morbid phznomena by a re- 
ference to acid and alcaline predominance. 
But no medical hypothesis has conferred reputation upon 
inert substances, to the same extent as the Doctrine of Signa- 
tures, which assumes that “ every natural substance which pos- 
sesses any medicinal virtue, indicates, by an obvious and well 
marked external character, the disease for which it is a remedy, 
or the objects for which it should be employed.” Paracelsus, 
Baptista Porta, and Crollius, were renowned advocates of this 
speculation. Thus the lapis etites, which is a hollow pebble 
containing another loose and rattling within it, was considered 
as effectually preventing abortion when worn upon the arm, 
and as promoting delivery when fixed upon the thigh. The 
lungs of a fox were regarded as a cure for asthma, because that 
animal is remarkable for strong powers of respiration. Turmeric 
is yellow, and therefore good for the jaundice. Poppies have 
heads, and hence their influence upon that part of the body. 
Upon the same principle the long pods of the cassea fistula must 
