Mr. J. Lowe on the Development of the Yeast-plant. 307 



Penicillium glaucum in wort under the same circumstances as in ex- 

 periment 1 . The same series of phsenomena ensued, ending in the 

 production of good yeast. A third and fourth experiment were made 

 with Aspergillus glaucus and A. nigrescensy with Hke results, the 

 only difference being that the sporules produced by the latter were 

 at the commencement larger and more spherical than in either of the 

 other species, from which it may be inferred that this species would 

 yield a better kind of yeast. The idea that yeast can be produced 

 spontaneously in nitrogenous fluids, we hold to be entirely erroneous, 

 for we see that the lower class of Fungi are capable of yielding it, 

 and from the general distribution of these, they must be present in 

 every kind of exposed fluid. 



Another subject which has not received the attention it deserves, 

 is the growth of Fungi on malting barley. Whole floors of malt 

 may be seen in summer-time covered completely with various Fungi, 

 which grow from the interior of the grain, and ramify within the 

 perisperm. These must have a most important influence on the 

 saccharine matter contained in the grain, and there can be little doubt 

 that they effect its decomposition, and cause an immense loss to the 

 brewer. The fact that malt made in summer-time is never so sweet 

 as that made in winter, sufficiently attests to the truth of this ob- 

 servation. It is not improbable, where the fungus is so abundant as 

 I have sometimes seen it, that one-third of the saccharine principle 

 is destroyed, and the foundation laid for the inefficient working of 

 the wort during fermentation. 



In conclusion, I would merely remark upon one or two cases of 

 skin-disease which I have met with in those engaged amongst the 

 yeast in breweries. Brewers, generally speaking, are not likely sub- 

 jects for the growth of parasitic plants, but I have met with several 

 cases which seem to me to prove that these are derived from the 

 growing yeast, and thus tend to establish the proposition laid down 

 in my last communication regarding the origin of skin-diseases. In 

 one brewery I met with two cases of psoriasis annulata, and one of 

 mentagra. These occurred in the only persons who were engaged 

 amongst the yeast. The former were both situated on the right 

 upper extremity, in the one case on the back of the hand, and in the 

 other, on the anterior surface of the fore-arm, about 3 inches above 

 the wrist. It commenced as a small red spot, and in eight days had 

 attained to the size of a shilling. On examining it carefully under 

 the microscope, a distinct mycelium was obtained, differing in no 

 respect from the same growth in favus, with a recent specimen of 

 which it was compared. I have not yet had an opportunity of 

 making inquiries at all the other breweries, but I have little doubt 

 that other instances of a like nature will be found. Drawings were 

 exhibited in illustration of Mr. Lowe's observations. 



6. *' List of Desmidiese observed in the neighbourhood of Dundee,'* 

 by Mr. W. M. Ogilvie. Communicated by Mr. G. Lawson. 

 This list embraced upwards of fifty species, many of them rare. 



20* 



