iv AUTHORS’ PREFACE. 
of physiological plant anatomy in its details is still in need of 
completion and general recognition, the outlines of the same 
appear to us, nevertheless, to be sufficiently well defined to 
be able to serve, in the manner intimated, as a foundation. 
In one point, however, we have departed from Haberlandt’s 
classification. The cell, its contents, and its membrane have 
been treated by us in a more complete manner, and placed be- 
fore the tissues. This deviation recommends itself for practi- 
cal and didactic reasons ; for the beginner must be instructed 
regarding the cell and its contents before learning anything of 
the tissues. The substances contained in the cell also possess 
too great an interest for the pharmacognosist to be inserted 
in the text simply in a secondary manner. 
A second change, as already intimated, is that we have like- 
wise made a place for technico-microscopical investigation, of 
which every one will approve who takes into consideration the 
extent to which the apothecary of our day is called upon as an 
expert. In order to aid in furthering this service of phar- 
macy, which is of general interest, we have, for example, 
treated more thoroughly of starch and the textile fibres, 
In the morphological portion, which has experienced a 
complete transformation, we have endeavored to give a 
brief sketch of the most important phenomena, whereby 
the technical expressions in present use have received explana- 
tion, especially those which occur in the deservedly widely 
distributed Syllabus of Eichler. Here, as in the anatomical 
portion, we have drawn the narrowest boundaries, since the 
present work does not pretend to be a complete text-book or 
manual. Nevertheless, some few sections which are of im- 
portance to pharmacy have received relatively somewhat 
greater development and more precise adaptation, as for ex- 
ample, that relating to the receptacles for secretions. A chap- 
_ ter on the galls has also been newly inserted. 
_ In the selection of the woodeuts, we have chiefly considered 
the drugs and crude substances of technical application. The 
