262 PLANT ANATOMY. 
is already evident from the description of the latter. In young 
cells, where the resin is first formed only in small amount, it is 
destitute of any special color; the same is the case where the 
resin forms semi-liquid granules, especially in those plants 
where it occurs emulsified as a constituent of laticiferous juices, 
for example, in Tuber Jalape. ‘This extremely fine division 
and liquefaction of the resins is promoted in the laticiferous 
juices of the Umbellifer by the volatile oil which they contain. 
Under such conditions the resin may be recognized by its 
tendency to absorb coloring matters. Iodine solution, or pre- 
ferably aniline colors dissolved in water, carmine, etc., when 
carefully added in corresponding amount, are very useful for 
this purpose. To be sure, this does not always prove that the 
colored bodies are resins, but the coloration, nevertheless, affords 
good points of discrimination. 
The schizogenic secretion-receptacles are generally closed. 
There are, however, cases where the secreting space is open, and 
communicates with intercellular spaces of the parenchyma, 
which likewise sometimes contain a secretion (Ozalis floribunda, 
Peganum Harmala, Lysimachia Ephemerum). 
With regard to their morphology and the nature of their - 
development, the following varieties of secretion-receptacles 
should, therefore, be maintained distinct: 
I. True Cells. 
(a) Isolated in the interior of the tissues, and on all sides in 
connection with the other elements of the tissue. 
1. Containing oil: Macis, Laurus, Cortex Angosture, 
roots of the Zingiberacee, Acorus Calamus, Cinna- 
mon bark. 
2. Containing mucilage: Cinnamon-bark, Elm-bark, 
Althea root (filling entire tissues in Chondrus). 
3. Containing laticiferous juice, simple: galls, from 
species of Rhus, from Eastern Asia : Euphorbiacee. 
4, Containing crystals, especially in monocotyledons. 
5. Containing tannin. 
@: ‘United in a band of cells. Fructus Conti, Tuber Jalape, 
_ Dichopsis Gutta. 
