386 MR. H. H. W. PEARSON ON SPECIES OF 
flow into the outer pitcher. If this be a possible function of 
the inner pitcher, it is not without interest to note that it has 
recently been suggested that ants resort to the Cecropias and 
other “ myrmecophilous ” plants of the Amazon Valley only in 
situations and under circumstances in which there is danger of 
their nests being flooded if made at a lower level *. 
Inside the three inner pitchers of D. pectenoides which I was 
able to examine, I found a large number of small irregularly 
shaped masses which were quite sweet to the taste. Between 
the teeth they crumbled like so much chalk. On examining the 
wall with a view to ascertaining their origin, I found that the 
outer tissues of the convex side of the neck were in an advanced 
stage of decomposition. Yellow strings of cells embedded in 
mucilage hung from the wall, and were clearly the source of the 
yellow masses in the pitcher below. The appearance was very 
remarkable, and one who saw the most marked of the three 
cases aptly likened it to a stalactite. When submitted to 
microscopic examination, these masses were seen to consist of 
parenchymatous cells with highly euticularized walls, and here 
and there a tracheid, embedded in mucilage which quickly 
swelled up in water. The blue colour with copper sulphate and 
potash, characteristic of cane-sugar, was obtained. Numerous 
fupgus-hy phe were present in the mucilage. Signs of a similar 
decomposition were detected here and there in the wall of the 
outer pitcher, usually in places were a callus had been formed. 
The callus appeared to be the result of an injury—probably an 
ant-puncture,—was circular in shape, and usually had a circular 
depression or hole in the centre. A transverse section showed 
a layer of periderm, beneath which was a mucilaginous mass 
embedding ordinary parenchymatous cells, some with apparently 
unaltered cellulose-walls, others in which the wall was strongly 
cuticularized. Fungus-hyphe occurred here as in the former 
case. I did not observe a similar decomporition in the pitchers 
of the other species, but owing to the very limited supply of 
material I am unable to say that it does not occur. This 18 
obviously a patbological condition, and is probably brought 
about by the combined action of ant-punctures and fungus- 
growth. It is strongly suggestive of that form of tissue- 
degradation known as “ gummosis.” The presence of sugar 1? 
the product of decomposition suggests its use by the ants as 
* Buscalioni & Huber, Beiheft zum Bot. Centralbl. Bd. ix. (1900) pp. 85-88. 
