166 FROCEEDINGS OF SOCIETIES. 
but a modification of the equally enigmatical movement of Oscil- 
latoria and Spirulina; nay, even in certain Nostochacee a certain 
amount of movement is evidenced not unlike that of Vibrio. 
Dr. Barker had before found Bacteria in urine. 
Mr. Tichbourne exhibited a longitudinal section of the wood of 
the soap-bark-tree of South America (Quillaria saponaria). He 
then read the following extract from a memoir by Professor S. Bleck- 
rode, Delft, Holland :—“ The bark is remarkable for its density, 
as it sinks in water. ... The cause of this is the immense quantity 
of mineral substances which it contains..... The ash consists 
almost entirely of carbonate of lime, which forms 12 per cent. of 
the whole, and appears as small crystalline needles, isolated or in 
groups, in the cells of the liber, not only between its concentric 
rings, but in every part of it. These glitter in the sun, resem- 
bling under the microscope the arragonite form of the crystallized 
carbonate of lime. The carbonate-of-lime crystals are generally 
characteristic of plants in which mucilaginous and pectinic sub- 
stances are formed abundantly.” Mr. Tichbourne said, from some 
experiments of his own, he was of opinion that Professor Bleck- 
rode was inerror. The crystals were evidently not carbonate of 
lime, as they were seen under the microscope to dissolve very 
slowly when placed in dilute hydrochloric acid, and without the 
evolution of gas. If they were carbonate of lime they would 
dissolve instantly in the acid, with a copious evolution of carbonic 
acid. They were evidently some organic compound of lime, which 
would, of course, yield carbonate of lime on gentle ignition, and 
thus probably arose the statement. Mr. Tichbourne said that the 
quantity of bark at his disposal did not admit of his determining 
what this organic substance was, but he hoped shortly to be able 
to do so. 
Dr. Frazer said that the crystals found so abundantly in quil- 
lai bark appeared, from his investigations, and from a careful 
examination of their microscopic form, to be compounds of bi- 
malate of lime. 
15th December, 1864. 
Read the minutes of the preceding monthly meeting, which 
were passed and signed. 
Dr. Barker showed five living specimens, which had been grow- 
ing upon a specimen of Dytiscus marginalis, of an Opercularia 
supposed O. articulata. The superior lip, supported by a muscle 
giving the same somewhat the appearance of an operculum, gives 
the name to the genus, and distinguishes it from Epistylis. The 
present specimens were large, broadly elliptic when shut in, and 
corrugated at the upper extremity; the peduncle stout, and beau- 
tifully and finely longitudinally striate. Without a reference to 
Stein’s figures, and more accurate descriptions, it would not be 
easy to come to a more decisive opinion as to the species from the 
