PHARMACOLOGICAL HISTORY OF QUASSIA. 
37 
their ashes. But the time has not come, to say upon what 
this supposition is founded. I return to quassia. The points, 
or rather the numerous small black lines observed upon the 
longitudinal section of this wood, according to M. de Lens, 
who has made an anatomical examination of them at my so- 
licitation, are the extremities of the medullary rays. Each of 
them, seen by the microscope, represents a large fusiform 
cellule, colorless by itself, containing two rows of small 
rounded cellules, dotted and colored violet black, doubtless 
by the globuline which they contain. The larger cellules 
are circumscribed on all sides by elongated cellules of the 
wood, or ligneous fibres possessing the same form, but hollow 
and transparent, which compose the major part of the wood. 
They establish a direct communication between the medulla 
and the bark, that is to say, between the cells constituting the 
parenchyma or cellular tissue proper; it is from these black 
points, the seat of an azoted substance, and very apparent 
upon the polished wood of quassia, that the nitrate of potassa 
issues, under given circumstances, and which I have not 
been able to determine, but in producing which, air and light 
seem to have an important part. 
In fact, of twenty goblets of quassia kept during two years 
in a glazed cupboard, exposed to a diffuse light, and which 
was frequently opened during the day, only three of them, 
that had remained uncovered, exhibited upon a portion of 
their exterior parietes, that upon which most light had fallen, 
the saline efflorescence in question. All the others, wrapped 
in a double white paper envelope, exhibited nothing of it. It 
remains to be determined, if the nitrate of potassa collected 
upon the quassia, formed part of that pre-existent in the sub- 
stance of the wood, or whether it be the product of new 
reactions on the part of the azoted matter and the organic 
salts with potassa for their basis, which are conjoined with it. 
This last explanation is, in my opinion, the most plausible. 
