282 PROCEEDINGS OF SOCIETIES. [^o^rS, SSrS^ 
fervoid growth, the sides of which were covered with cells filled with 
pseudo-naviculsB. When examined by transmitted light the fluid gave 
a delicate bluish pink colour, and bj r<^flected light a reddish hue. 
Under the micro-spectroscope, its spectrum is just that described by 
Mr. Browning in vol. vii., 1867, of the Society's ' Transactions.' A 
few pieces of camphor serve to preserve the fluid ; and although the 
specimen exhibited had been corked up for several months, the colour 
is nearly as good as when it was fresh gathered, and the spectrum 
reaction quite perfect. 
The President then requested Mr. Carruthers to read a paper on 
the " Plants of the Coal-measures." 
Mr. Slack wished to call the attention of Fellows conversant with 
crystallography to the curious instance mentioned by Mr. Carruthers, 
in which, after the charring of the vegetable structure, although the 
particles of carbon preserved the exact form of the vegetable cells, 
they had opposed no obstacle to the crystallization of the carbonate 
of lime, which had gone on through their interstices as though no 
obstacles had intervened. 
Mr. C. Brooke stated that structure is much interfered with by 
foreign matter — the sandstone of Fontainebleau, for instance, assumes 
the form of rhombohedral crystals of calcite. The stone does not 
contain more than 5 to 7 per cent, of carbonate of lime ; but the 95 per 
cent, of silex seems to be dragged into form by the 6 per cent, of car- 
bonate of lime which controlled the character of the crystallization. 
Dr. Murie alluded to the preservation of the form of straw after 
carbonization in a furnace. 
Mr. Browning suggested, as an important line of research, that 
certain organic fluids should be mixed with solutions of crystallizable 
substances, in order that it might be seen in what cases the organic 
matter would be enclosed in the crystals formed by evaporation. 
Dr. Lawson hoped that the Fellows would employ a little of the 
time hitherto devoted to the study of Diatoms, &c., to the interesting 
questions brought forward by Mr. Carruthers. With reference to the 
remarkable combination of types mentioned by Mr. Carruthers, he 
would ask whether he considered these cases as corroborative of the 
Darwinian doctrines ? 
The President said it was satisfactory to note the important ser- 
vice rendered by the microscope in Mr. Carruthers' investigations. 
He thought Dr. Murie's remarks not exactly parallel to the instances 
adduced by Mr. Carruthers. Dr. Murie showed that the process of 
carbonization did not interfere with the form of the original structure 
of the solid material of plants ; but this was not the point taken up 
by Mr. Carruthers, who showed that the process of crystallization was 
not interfered with by the presence of foreign matter. He (the Pre- 
sident) had tried several experiments with cereal plants, which he 
burnt in a platinum spoon, and found that by taking a small portion 
of the siliceous residue, which he could just see with the naked eye, 
and placing it under a ith glass, that the beautiful conformation of the 
solid structure of the plant was distinctly seen. The President then pro- 
posed a vote of thanks to Mr. Carruthers for his interesting address. 
Mr. Carruthers in expressing his acknowledgments for the manner 
