74 Miscellaneous. 



and structure of the spicula of sponges in general, and endeavours 

 to prove that they bear no relation to the raphides of vegetable 

 bodies, but are truly of animal origin, having their internal surfaces 

 lined with an animal membrane, which becomes converted into a 

 thin film of carbon when the spicula are exposed to the action of the 

 blow-pipe. 



The author illustrated his paper by numerous drawings of the tis- 

 sues described, and exhibited the specimens from which they were 

 delineated. 



Mr. Owen exhibited the specimens of the teeth of the Labyrintho- 

 don, described by him at the last Meeting of the Geological Society, 

 and he explained the peculiarities of the dental structure in that 

 extinct species of Reptiles. 



Mr. Varley called the attention of the Society to a new form of 

 Microscope, which he had constructed with a view to facilitate the 

 examination of minute living objects. 



MISCELLANEOUS. 



Absorption of Liquid Solutions by the Sap-vessels of Plants. — M. 

 Dumas reported to the Academy of Sciences on the 30th November, 

 1840, that by the absorption of various fluids. Dr. Boucherie had dis- 

 covered a method of rendering wood more durable, of increasing its 

 tenacity and hardness without impairing its elasticity, and of im- 

 parting to it various permanent colours and odours. 



Dr. Boucherie found that the attractive power of the vegetable 

 tissue was sufficient to carry from the base of the trunk to the leaves 

 all the fluids he wished to introduce, ])rovided they were kept within 

 certain limits of concentration. He cut a tree near the base when 

 in full sap, and plunged it into a tub containing the fluid he wished 

 to introduce, and in a few days he found that it had risen even to the 

 most elevated leaves, and had penetrated all the tissue except the 

 heart of the tree. The same result followed whether the trunk was 

 in an erect or inclined position. It was not even necessary to divide 

 the trunk completely, for a cavity hollowed out at its base, or a 

 groove made with a saw over a considerable part of the circumfe- 

 rence, was sufficient, when the cut part was brought into contact with 

 the fluid, to allow a rapid absorption to take place. 



Dr. Boucherie ascertained that the absorption of a solution of 

 pyrolignite of iron containing some creosote augmented the hard- 

 ness of wood and prevented its decay, while the penetration of the 

 wood with solutions of the earthy chlorides and various saline mat- 

 ters rendered it less combustible. 



Various colours were given to wood by causing diff'erent substances 

 to be absorbed in succession. Pyrolignite of iron by itself gave the 

 wood a beautiful brown colour; when it was followed by an astringent 

 fluid containing tannin, a blue, black, or gray colour ensued ; and 

 when succeeded by ferrocyanate of potash, a deep Prussian blue re- 



