68 



Prof. W. C. Williamson on the 



[May 18, 



effected by quinine, namely by irritation of the inhibitory centres within 

 the head. As the whole subject of the action of quinine on the functions 

 of the spinal cord is at present unsettled, too much stress must not be 

 laid on this action of picrorocellin. 



"3. "When an ethereal solution of picrorocellin is added to an alkaline 

 solution of sulphate of indigo, with blood and ozonized turpentine, in the 

 manner recommended by Binz and employed by him in his researches on 

 quinine, the production of isatin is not in the least retarded, whilst qui- 

 nine retards it very greatly. Picrorocellin thus differs from quinine in 

 not arresting oxidation, a most remarkable characteristic of the latter. 



" I regret that I have been unable to test it chemically in a case of 

 ague, as the patients I see come and go so irregularly that little or no in- 

 formation would be gained by administering it to them. The sparing 

 solubility of picrorocellin is a serious objection to its use in medicine, 

 even supposing it to have the same properties as quinine ; and as it does 

 not possess one of the most important of these properties, there is no 

 probability that it can ever be used as a substitute for quinine." 



IV. " On the Organization of the Fossil Plants of the Coal- 

 measures. — Part VIII. Ferns (continued) and Gymnospermous 

 Stems and Seeds.'' By Prof. W. C. Williamson, F.R.S., 

 Professor of Natural History, Owens College, Manchester. 

 Received May 2, 1876. 



(Abstract.) 



Ferns (continued). — Under the name of Rachiojpteris corrugata a small 

 item of a fern is described, the outer surface of the bark of which is corru- 

 gated with innumerable transverse ridges and furrows. It has a vascular 

 axis in its centre composed of several clusters of barred vessels filled with 

 tylose, which clusters are blended together at their periphery, forming a 

 cylinder ; its centre is occupied by a cellular medulla, mingled with small 

 vessels, which sends off radiating prolongations into the vascular cylinder, 

 partially separating the bundles of the latter. Besides this cylinder is a 

 second, smaller, isolated oval bundle, which soon escapes from the stem as 

 the centre of a petiole ; but before it does so a new one is detached from 

 the opposite side of the central cylinder, which, in turn, imitates its pre- 

 decessor. Besides these primary bundles, numerous secondary smaller 

 ones are detached, sometimes from the central cylinder, sometimes from 

 near the bases of the petiolar bundles ; these probably supplied rootlets. 

 The author points out that this fern, along with the 'Anachoropteris 

 Decaisnii and the '^Zygopteris Brongniarti of M. Renault, constitute a 

 group of ferns having a very distinct type of stem-structure different 

 from what is found in the rhizomes of recent ferns, and which approxi- 

 mates to the lower LepidodendroiH stems represented by L, Harcourtii. 



