The Presidenfs Address. 77 



intimating his intention to pursue the subject further, he con- 

 ckides, " I shall also endeavour to repeat your experiments 

 with albumen, the influence of which upon the colour seems 

 very curious after your investigations." 



The Rev. J. B. Eeade exhibited a " thousand grain " bottle 

 of the dichroic fluid at the Society's Soiree, and Messrs. 

 Sorby and Browning have described its remarkable spectra. 

 In a letter from Rev. J. B. Reade, dated Feb. 3, 1868, he 

 informs me that the convervoid mass, which produced that 

 splendid colour in a solution of albumen, is growing again, 

 and that Mr. Sheppard will soon gather it again in velvety 

 sheets, in sufficient quantity for different observers to work 

 upon, and no doubt Ave shall soon know the truth. 



The second paper referring to minute organisms was by 

 our Hon. Secretary, Mr. Slack (read in December), " On a 

 Ferment found in French Wine," corresponding in proper- 

 ties with M. Pasteur's Mycodenna vini, and shown to be one 

 of the series of forms assumed by the Yeast plant, the Blue 

 Mould Penicillum glaucum, Sec. It was incapable in its original 

 state of exciting either vinous or acetous fermentation. 



The subject of Micro-chemistry and Toxicology came be- 

 fore the Society in a paper read in October by Dr. Guy, " On 

 Microscopic Sublimates." This paper was richly illustrated 

 by specimens of the objects described by photo-micrographs 

 of Dr. Julius Pollock and Dr. Maddox, and by drawings of 

 Mr. Tuffen AVest. By carrying further than previous ob- 

 servers had done the preparation and examination of micro- 

 scopic sublimates, Dr. Guy has opened new and important 

 fields of inquiry and analysis, which bid fair to be useful in 

 medico-legal and other investigations. His preparations were 

 remarkable for the elegance and variety of their forms, and 

 for the very small quantities of matter which sufficed to pro- 

 duce them. In one instance -roV-irth of a grain of crystallized 

 strychnine yielded nine distinct sublimates in succession, and 

 among them there must have been one Aveighing less than 

 the y-ij-L_oth of a grain. 



Notwithstanding the difficulties arising from the existence 

 of isomorphic bodies and the changes in crystalline forms, 

 resulting from peculiar conditions, and the presence of sub- 

 stances interfering with normal results, there is reason to 

 hope that processes of this description may in many cases 

 yield definitely characteristic indications, and in others afford 

 evidence which may be of great importance as portions of a 

 chain of proof; and Dr. Guy's researches will be regarded 

 as all the more valuable from the difficulties that frequently 

 attend ordinary methods of investigation. 



