Occasional Notes. 129 
much from that of the East Indian latex -yielding trees, being a thick, 
almost pasty, liquid of white appearance and sour smell. It would not 
filter clear through paper and was therefore submitted to the action of 
the filter-pump used before. The diluted filtrate, and a watery extract 
of the dried residue, were taken for examination. 
The solution thus obtained proved on investigation to contain two 
proteid bodies, which could be separated from each other with tolerable 
ease. On heating the solution gradually, having first neutralised, 
a little opalescence appeared, but it did not become particulate even at 
the boiling point. When the liquid was made either acid or alkaline 
however, it behaved differently. In a nitric acid solution an opalescence 
was noticeable when the temperature had risen to 85 — 90 C. This was 
not removed by the addition of more nitric acid. On keeping the 
vessel for some time at this temperature, the opalescence became a 
precipitate, which was soluble at ordinary temperatures in alkalis, 
slightly so in water, but not in nitric acid. The solutions gave the 
xanthoproteic reaction. A curious point about this body was the 
slowness with which the precipitate formed, it appearing not at all like 
the usual conversion into coagulated proteid on a rise of temperature, 
but more like a slow precipitation by the reagent at that particular 
point. This was confirmed by several experiments, one of which, often 
repeated, was the following. A quantity of the extract was made acid 
with nitric acid and warmed to 75 C, a point considerably below that 
at which the precipitate was first observed to form. It was then allowed 
to cool, and as the temperature was gradually falling, the precipitate 
slowly separated out. The body seemed then to be slowly precipitated 
by nitric acid, but not at the ordinary temperature. 
In an alkaline solution its behaviour was somewhat different. The 
opalescence set in at 79 C, and a bulky precipitate settled out slowly at 
85°C. This was soluble to a large extent in nitric acid, and was 
reprecipitated when the liquid was made alkaline. A solution in caustic 
soda of the precipitate caused by nitric acid at 85 C. behaved similarly. 
The precipitation here also seemed to be caused by the reagent and not 
by the temperature, for the alkaline liquid deposited the proteid body 
on cooling just as the acid one did, and in about the same time as when 
the temperature was kept constant at 85 C. Both precipitates were 
unaltered in the separation ; each went into solution readily in 
its appropriate medium, the solutions a] giving the xanthoproteic 
reaction. 
R 
