epidermis”. He thus proclaimed the specs of the thesis consider asa ina of 
The epidermis has merely the function of a periphere : water-tissue and forms a water. 0 
In the course of several years, the examples increased considerably in number. A 
alcaloids, Tschirch’s thesis was confirmed for nearly every plant examined. Almost 
same holds good for the glucosides. They likewise distinctly prefer the epidermis, r 
only the hesperidine, but it is still more the case with a third group of bodies, 
tannides, as quite recently Dekker’s investigations have shown, who by introducing 
branches into a potassium acid chromate solution ee the tannige substan 
in loco, thus avoiding any misunderstanding. ae 
The results of the various investigations point to a severe division of labour in t . 
chemical work. Alcaloids, glucosides and tannides are formed as little in the places a 
assimilation as in the ducts, these being carefully kept free from such substances. 
A certain chemical antagonism corresponds with this topographic-anatomical onal 
the acylic compounds, the hydrocarbons and the albumens are formed and conveyed — 
in tissues absolutely free from cyclic compounds. These, such as alcaloids, glucosid 
with cyclic aglucone, such as tannides, are found in other tissues, in the’ epidermis and — 
the immediate vicinity of the fascicles. They have in no case been conveyed to these 
places, but have been formed there. The cells and tissues in question must therefore ~ 
have the power of closing the ring of the originally acyclic system, for in the ssi 
lative process only acyclic carbon compounds form and only such wander. As soon as” 
the ring is closed, a terminal point of a range has been reached. The cleavage of the 
ring and with it the retrocession into the assimilative process is very rare in any case. © 
It happens only under quite exceptional souls he rapt most likely only in case of eX” 
treme need. \ ea 
The typical closing of a ring, through which an acyclic system becomes ‘rene is. 
shown us in the transformation of a hexose, known to be acyclic, into a cyclic inosite. 
Also in the case of the alcaloids, the closing of rings is to be supposed. It is the a 
same with tannides, for the prototannides are aromatic phenoles, which we likewi 
can imagine as having formed from hexoses by the closing of the ring, connect L 
with a reduction or with water being split off. It is true, that the closing of the | ing 
does not always lead to tannides, sometimes the sweet taste is retained, such as wi 
phloroglucine and the product of its reduction; viz., phoroglucite, corresponding 
inosite. With alcaloids as well as with tannides, it is ¢6 be observed that. they comb 
with saccharides, and especially with hexoses, to form glucosides. The alcaloids 
it rather seldom; but the tannides, fairly frequently. The non-tannidish gluc 
form a great class. The constitution of the aglucone of many glucosides has 
been determined as yet. That of the hesperidine is known. It is called hesperi in if 
Power and Tutin have recognized it as 2, 4,6-trihydroxyphenyl-3-hydroxy-4-methoxys 
ketone. In addition to alcaloids, tannides and glucosides, red colouring ma 
in the epidermis of leaves. The anthocyane, for example, is also, ¢ a L cyclic c 
derived from flavonole, as Willstatter has shown, 
1) Regarding hesperidine as a pathological product of the peppermint plant, comp. Report 
