orange coloured Algae and iron was being deposited. I have also 
met with cylindric casts of roots, in haematite. One of these casts 
is & an inch in diameter and perforated by a tube one-tenth of an 
inch across evidently corresponding to a root since decayed. 
A similar case of the formation of iron-pan by an Alga ( Gaillo - 
nella) is mentioned by Lyell in his Geology, and it is possible that 
all these oxide of iron deposits are caused by Algae, or Bacteria. 
I have called this plant an Alga and some Botanists consider it 
so, but De Bary and others class it as an A rthrosporous Bacterium. 
The figure he gives of Crenothrix Kuhniana, (Morphology and 
Biology of Fungi, p. 470 fig 196) considerably resembles this plant, 
but appears to be bigger and it is difficult to see the characteristic 
breaking up of the filaments figured by him in the Singapore plant. 
The cocci and zoogloea forms are however quite similar. He men- 
tions it as a Schizomycete which occurs frequently in water contain- 
ing some amount of organic substances and sometimes in quantities 
which are dangerous to health, and indeed it seems to be a most 
objectionable plant in water. 
Crenothrix A s not the only Alga which gives an orange coloring- 
to the water here, as on the Enhydrias and on Utricularia I 
found an abundance of fusiform Diatoms of a reddish yellow colour 
which were arranged in strings one over-lapping another, which 
gave an orange colour to the leaves of the weeds. It appeared to 
be a species of Pleurosigma. 
It has been said that ponds have been completely cleared of 
Algal scum in Ceylon and ehewhere by the use of copper sulphate 
m sucn small quantities that animal life is not injured and the water 
r V nams P u , nfied % n ? fit for human use. This apparently is not 
efficacious here, he quantity of copper sulphate required to pre- 
cipitate the Crenothrix, is too great to be safe to use, and in ponds 
with shallow shaded edges the plant grows so rapidly that in a few 
days it is as bad as before. It can also apparently thrive under 
ground in water following the courses of roots so that it can be 
conveyed through springs, growing along the roots 
Action of Copper sulphate on other aquktic plants— A quantity of 
Utricularia stellata growing in the Garden’s Lake was taken and 
put into two jars filled with water as in the case of the Crenothrix 
One jar was treated with copper sulphate J oz. to the jar. The 
other untreated. The Utricularia was swarming with rotifers, para- 
moecia, minute larvae and other animals, besides containing numerous 
diatoms, desmids, and other Algae of different kinds. The day after 
the copper sulphate was added, a good deal of the Utricularia was 
lound to be dead and there were no signs of animal life except at 
r a - W PwMn&cia* Dead insect larvae were seen at the bottom 
ot the jar. In the untreated jar the rotifers, vorticellas and other 
an^h eM thy 6 rC ^ thriving and the Utricularia was green 
olfVr r w m 5 !i kable thing n ° ticed about this Utricularia was that the 
older bladders, apparently those that had caught infusoria, were of 
