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the gravel, consisting of pebbles of grit from the coal measures. Mr. Bed- 

 ford also showed ice-scratched blocks of chalk and limestone, the former 

 from the glacial drift of the Yorkshire coast, near Bridlington (derived, no 

 doubt, from the Chalk Wolds to the north-west), and the latter from 

 Menston, near Guiseley. H. Bendelack Hewetsou also sent specimens of 

 ice-marked stones, and an ice-scratched Mammoth tooth, in which the 

 dentine of the tooth was still remaining. These also were found in the 

 glacial drift of Holderness. J. E. Bedford exhibited also specimens 

 of plumbago or graphite from the Buckingham Mines, near Ottawa, 

 Canada ; and he explained at some length the appearance of the veins 

 in the Laurentian gneiss and crystalline limestone of that district, in which 

 the substance is found. 



Other exhibits consisted of a series of microscopical slides of jaws and 

 lingual ribbons of mollusca, prepared by J. D. Butterell, and shown with 

 polarised light. 



June 19th, 1885. 



F. W. BEANSON, F.C.S., on "BACTERIA." 



The paper opened with references to the able and eventful researches 

 of Pasteur, to whose labours may be indirectly traced the system of 

 antiseptic surgery initiated by Sir Joseph Lister. From the fact 

 that organic substances remain unchanged for any length of time 

 in perfectly pure air, i.e., air free from germs, whereas putrefactive 

 changes soon commence if the same substance is exposed to ordinary 

 atmospheric conditions which allow the access of germs, it may 

 safely be assumed that the changes are due to micro-organisms, 

 which, indeed, appear in great numbers. Bacteria being the most 

 numerous and important, the first organism which usually appears 

 being Bacterium termo, the smallest of the Bacteria, the one-hundredth 

 part of a cubic inch being equal to 50,000,000 of these organisms. At 

 this stage a series of slides, showing the appearance of a fish infusion at 

 stated intervals, were exhibited on the screen. The question. What is a 

 Bacterium ? was then considered, the general characters and afiinities 

 of these universally distributed organisms being described in detail, as 

 were likewise the spore and zooglea forms of the Bacteria. The classifica- 

 tion of Cohn was adopted by the speaker with some reservation, being 

 based, he considered, too much on morphological characters, e.g., the 

 knowledge of the division Micrococci, in which the spore formation is 

 unknown, being evidently incomplete. Cohn's system must, therefore, 

 be regarded as partly provisional. Classification from a chemical point of 

 view was then noticed, and the following well-defined groups described : — 

 Septic or puti-efactive bacteria, zymogenic bacteria, and pathogenic 

 bacteria. Bacteriicm termo is a type of the first group, and is always to 

 be found in putrescible liquid, the function of the organism being to break 

 down complex organic molecules with the concurrent formation of simpler 



