471 



their nature. Their form is not constant, and under the microscope I 

 sometimes find it impossible to distinguish them from the grains of 

 starch. I cannot, besides, detect any determinate arrangement of the 

 granules, which the microscopical observer would naturally expect to 

 exist in a series of more or less spherical organic bodies. Certainly 

 the brown spots in the tuber require more investigation than they (so 

 far as I know) have received. My attention was directed to the pota- 

 to-disease late in the season, and no opportunity was afforded me of 

 examining the leaves or the stalks. It has struck me, however, in 

 reading Mr. Berkeley's valuable memoir, that the black spots on the 

 stalk, where the cellular tissue is described as filled with a dark, gru- 

 mose mass, may correspond with the brown spots in the tuber, the 

 cells of which contain the brown, grumose granules, and that the one 

 may throw some light on the other. 



Mr. Walter Crum, of Glasgow, detailed his experiments on the 

 brown colouring matter of diseased potatoes, and stated that it con- 

 tained nitrogen, He had carefully examined the brown granules al- 

 luded to by Mr. Goodsir, but did believe it was a fungus. 



Dr. George Wilson was much interested in what Mr. Goodsir had 

 said in reference to the connexion between the disease in the potato 

 and the appearance of a fungus, and in the comparison which he had 

 drawn between it and a solution of sugar undergoing the vinous fer- 

 mentation, in which a cryptogamic plant always showed itself Dr. 

 Wilson was of opinion, however, that the vegetable physiologist was 

 not entitled to refer to the fungus as the cause of fermentation, or to 

 speak of it as more than an accompaniment. On the other hand, he 

 was free to acknowledge, that as the chemist could not point to a sin- 

 gle example of the vinous fermentation having been observed without 

 the saccharrmyces being seen also, he was not at liberty to explain 

 the fermentation without reference to the fungus, as he generally did. 

 Dr. Wilson believed that fermentation was at present an Oregon ter- 

 ritory in science, which the chemist and physiologist must, in the 

 meanwhile, agree to hold in joint occupancy till it could be settled 

 which had the best right to it, or on what terms it should be divided. 

 Mr. Goodsir had not done himself the justice to mention, that in a 

 remarkable case of disease in the human subject, in which the con- 

 tents of the stomach underwent a change exceedingly like that which 

 vegetable juices suffer when the lactic or viscous fermentation is going 

 on in them, he predicted the great likelihood of a cryptogamic plant 

 being found, and discovered a very curious one — the Sarcinula ven- 

 triculi. Dr. W. would suggest to microscopic observers, that it was 



