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the cells of the stomata, elsewhere none at all. If the microscopic 
sections are beforehand killed and extracted with alcohol, the enzyme 
spreads in the cell but remains confined within the cell-walls, 
so that, by putting them into an indican solution they become 
of a uniform intense blue, in which only the bast bundles remain 
colourless. 
The accumulation of enzyme in the chlorophyll-granules is perhaps 
connected with the formation of starch from the glucose of the indican. 
As to the localisation of indoxyl in the leaves of woad I have 
acquired no certainty, but I suppose that, like indican, it occurs 
only in the protoplasm. 
The hypothesis of Mr. Morrscr ') according to which indoxyl 
and indican should be in close relation to the decomposition of 
carbonic acid in the chlorophyll, appears contrary to the great 
accumulation of indoxyl in the root-peridermis, which is completely 
free from chlorophyll, and in the colourless root-buds of the woad, 
which seems unnoticed by Mr. Morrscm. Nor do I think his argu- 
ments and figures convincing for the occurrence of indoxyl and 
indican in the chlorophyll-granules; moreover was Mr. Morrscr 
unacquainted with the existence of indigo-enzymes and their local- 
isation. 
Elsewhere than in the indigo-plants indigo-enzymes seem but seldom 
to occur. Like Dr. van RompurGu ”) I observed that emulsine of 
almonds decomposes indican, and in $6 the intensity of this action 
is graphically represented in connection with temperature. 
The said fact may serve to demonstrate in a simple way the 
localisation of emulsine in almonds. If thin sections of the seed- 
lobes are put in an indican-solution at 50° C., the vascular bundles 
will first take a deep blue colour, which shows that there the emuls- 
ine is the most accumulated. Then the parenchyma around them 
grows blue, and finally the more peripheric parenchyma. This 
points out that the emulsine is nowhere wholly absent but is accum- 
ulated about the confines of the central-cylinder, which becomes 
distinctly visible by this experiment *). 
A rather great number of other plants examined for indigo-enzymes 
have all given negative results *). 
*) Berichte der deutschen Bot. Gesellschaft, Bd. 17, p. 230, 1899. 
2) Communicated by Mr. HAZEWINKEL, Maandelijksch Bulletin N® 1, pag. 8. 
*) Nearly the same has been found by JoHaNNsEN, who examined the decomposi- 
tion of amygdaline with separate parts of the seedlobes. (Ann. Sci. Nat. Botan. Série 
7, T. 6, p. 118, 1887). 
*) So I could not find indigo-enzymes in: Indigofera dosua, Polygonum persicaria, 
