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248 INTRODUCTORY LECTURE. 
and emulsin, two substances that react with each other in the 
presence of water with the production of the oil of bitter 
almonds and hydrocyanic acid. Boiling water coagulates 
emulsin and renders it inert, and hence if the distillation is pro- 
ceeded with at once the latter principle is made incapable of 
acting on the amygdalin before all of it has been decomposed, 
and the product is proportionably affected. 
From these examples the value of a knowledge of the com- 
position of drugs must be at once apparent, and its extension 
affords a field of research in organic proximate analysis, that 
has been occupied to some extent by the graduates of this 
school. 
It is in Pharmaceutical Chemistry, however, that the most 
interesting labours of the apothecary are to be found. Here he 
is governed by exact rules, and arrives at precise results which 
accord with the beautiful laws of definite proportion ; and as 
it were to harmonize, his products assume mathematical forms of 
definite character. 
The chemist deals in certainties — demonstration is his 
watch- word ; and the chemistry of the apothecary must par- 
take of this accuracy. Instead of the uncertain and varia- 
ble mixtures that have been noticed as resulting from the 
action of solvents on vegetables, he here has to deal with 
those curious organic principles upon which the activity of 
plants depend. In the discovery and isolation of these, 
pharmaceutists have contributed more than any others. 
The discovery of morphia by Sertuerner, opened to view 
that interesting field of research which has since been so in- 
dustriously cultivated, that nearly the whole Materia Medica 
has been compelled to pass through the laboratory to be ex- 
amined and cross-examined by its untiring votaries, until they 
have yielded up the secrets of their composition for the benefit 
of medicine. 
The Pharmaceutical Chemists of Europe are a body of 
which Pharmacy may well be proud; they have done more for 
the advancement of organic chemistry than any other profes- 
