EXTRACTS OF PROCEEDINGS. 
cliii 
power, by means of which he found that, although the clusters 
were very uniform in size and equal in distribution, they 
appeared to have no relationship with the stomata, were not 
collected at these openings, and evidently were in no sense to 
be attributed to exudation from the stomata. Further manipu¬ 
lation and dissolving away the crystals demonstrated that each 
of the clusters had a nucleus in the form of a globose glandular 
hair, with a very short stem. These glands occupied the centre 
of each cluster of meal, were quite empty and collapsed, with 
the broken crystals adhering to the surface covering them, and 
converting them into the appearance of clusters of meal. Thus 
far, then, the examination showed that the regularity of the 
disposition of the meal was due to the presence of globose 
glandular hairs, around which the meal was collected in the 
form of broken needle shaped crystals; and it may fairly be 
assumed that this meal is at first contained as a secretion 
within the glands, ultimately escaping and crystallizing upon 
the surface. 
In order to ascertain the chemical characteristics of this 
substance, he forwarded the small quantity which remained to 
him, after his experiments, to one of the expert chemists in the 
Laboratory of the Inland Revenue, and he thus reports the 
result of his investigation: “The meal on the auricula leaves 
consists of crystals which appear to be coated with a waxy 
matter. On removing the meal and treating it with alcohol, 
strength 50 o.p., all dissolve; but on evaporating the alcohol, 
beautiful acicular crystals rearrange themselves in a stellate 
manner. I believe the meal to be an alkaloid of some kind; 
the crystals are very fine. It is soluble in ether, soluble also 
in weak hydrochloric acid on heating, but precipitated on cool¬ 
ing. With a better supply of leaves, and more time allowed 
to me for the examination, I could probably have added to this 
report, which may be resumed with a better supply of material.” 
This, therefore, was the whole of the result of his present 
investigation, that the mealy substance is a secretion from 
certain globose glandular hairs, which is transuded and crystal¬ 
lizes in clusters on the surface of the leaves. That it is ap¬ 
parently an alkoloid, the precise nature of which has not been 
determined on account of insufficiency of material, but what are 
its uses or functions in the economy of the plant no conjecture 
n 
