TOME II, 1904. 
186 L. ERRERA. — SOME GENERAL RESULTS 
Dr. Maistriau and the lamented Dr. Clautriau. We used a great 
number of general as well as special reagents of the different alka- 
loids which we examined, for the sake of their mutual control. In 
consequence of the fact that many alkaloids are closely related to 
proteids, a great analogy exists in the action of many general 
reagents on both classes of compounds. This is, of course, a serious 
difficulty in microchemical determinations. But an alcoholic solu- 
tion of tartaric acid separates clearly the two groups, dissolving 
the former from the cells and leaving the latter undissolved, and 
this method has always given very good results. 
Similar lines of investigation have been followed with success 
within the last eighteen years by a number of my pupils and by 
many other observers, principally in Holland and Sweden; further 
also in France, Germany, and Italy. 
The more important conclusions arrived at by these researches 
(which must, of course, be conducted critically) might be summa- 
rised as follows : 
1. The qualitative and to some extent the quantitative distribu- 
tion of alkaloids (especially those belonging to the pyridic series) 
can be determined microchemically in the various organs of plants 
with perfect certainty. 
2. In living cells the alkaloids are eliminated from the proto- 
plasm and gather in the vacuole. It is only in cells which have lost 
all their liquid contents (as in ripe seeds) or in dead cells that they 
accumulate in the protoplasm or the cell-wall. 
3. The alkaloids are generally localised : 
a) In very active tissues : chiefly in the neighbourhood of grow- 
ing points (a little behind the initial cells), in the ovules, etc.; 
b) In the epidermis, the epidermic hairs, often also in the sub- 
epidermic layers of vegetative organs, as weil as the outer layers 
of fruits and seeds; 
c) Round the fibro-vascular bundles, in certain of their phloem- 
elements and in the neighbourhood of the pericycle; 
d) In the phellogen and the youngest cork-cells (either normal 
or consecutive to traumatism) ; 
e) In the laticiferous or similar elements, when present. 
