1046 KEroRT— 1898. 



from the Permian Formation. The author describes English specimens of Alfdi/l- 

 losa from the Lower (.^al-measures at Hough Hill, in Lancashire, found by Mr. 

 Lomax and Mr. "Wild. The specimens are thus from an horizon considerably 

 lower than those previously recorded. The stem is somewhat simpler in structure 

 than that of other Medulloscr, and shows very clearly that its organisation is 

 essentially that of a polystelic Hetcrangium. The Myeloo.ylon petioles are found 

 in connection with the stem, thus atl'ording new confirmation of the views of 

 Schenk, Solms-Laubach, and others as to the relation between the two supposed 

 genera. 



The triarch adventitious roots belonging to the MeduUosa stem are alsn 

 described. The new species illustrates with great clearness the remarkable com- 

 bination of Filicinean and Cycadaceous characters which the Medullosee present. 



3. On the Alcoltol- Producing Enzyinn in Yeast. 

 By Professor J. R. Green, F.R.S. 



At the meeting of the Botanical Section at Toronto last year the author ga>e 

 an account of some experiments which he had made during 1897 with a view to 

 confirming the work of Dr. Buchner on this subject. These experiments only 

 yielded a negative result. During the present year he has carried them fui-tlier, 

 giving attention particularly to the condition of the yeast at the time of the 

 preparation of the extract. He finds that at the time of very active fermentation 

 the enzyme can be procured as Buchner has stated. The author cultivated about 

 2 lbs. of a very pure yeast in an incubator, and, when the growth of the yeast was 

 at its maximum, he rapidly dried and ground it as Buchner recommends. Th« 

 expressed liquid immediately set up evolution of CO., in a solution of cane sugar, 

 maintaining for several days a free pressure in a manometer affixed to the flask in 

 which the operation was carried out. The liquid lost weight at the same time, 

 and there was a coincident formation of alcohol. The gas was proved to be CO.j 

 by leading it into baryta-water. When in a separate experiment it was absorbed 

 by potash the gain of weight by the latter corresponded to the loss of weight by 

 the fermenting liquid. 



The operation was conducted in the presence of excess of chloroform to securs^ 

 the absence of bacteria and to check the development of yeast cells should a few of 

 them have obtained admittance to the liquid. 



The enzyme agrees in an important respect with other enzymes. It is carried 

 down to a very considerable extent, if not completely, by the formation of an inert 

 precipitate in the liquid. 



4. A Potato Disease. By H. Marshall Ward, D.Sc., F.E.S., 

 Professor of Botany in the University of Cambridge. 



I have for some time past had occasion to recognise here and there, in various 

 parts of England, a potato disease which is not due to rhytojjhthora, and which 

 has often been ascribed to bacteria. During the past two years my attention has 

 been especially directed to testing its bacterial origin, and 1 am convinced it is* 

 not due to bacteria, but to a true hyphomycetous fungus. 



Without going so far as to say there is no bacterial disease of the potato, I 

 ■wish to express the conviction that the alleged cases of such lately published are 

 not convincing, and that a tendency exists to draw conclusions from imperfect, 

 evidence. 



I shall show that the way into the tuber is prepared for bacteria by fungus 

 hyphsD, and the open passages of destroyed vascular bundles afford them ampio 

 space. The disease I have studied has appeared in a more or less epidemic form 

 at least twice in my experience: it was very common two years ago, and this year 

 has been abundant in various parts of England. In a subsequent publication I 

 shall show that it is common and wide-spread, and even known in some countrie.'*, 

 though not adequately recognised. 



