196 PKOCEEDINGS OF SOCIETIES. 



ing, as well as of filtering. How far cliemical action operated in the 

 case of Mr. Bell's experiments it wonld be impossible to say without 

 further investigation. With regard to the different sorts of fermen- 

 tations, he thought it would be found that more than one fungus con- 

 tributed to vinous fermentation, and when vinous passed to acetous 

 fermentation it would be found due to the action of other sets of 

 fungi, and the same with butyric fermentation. If a piece of vinegar- 

 jjlant be taken and separated into successive sheets, and dried in the 

 oven, it would be reduced very much to the ajipearance of prepared 

 gelatine, and will even "chink" when thrown down on a plate. This 

 di'ied vinegar-plant would often excite butyric fermentation, and he 

 noticed a slight odoTir of butyric acid in one of Mr. Bell's bottles. 



Dr. Millar thought that Mr, Bell had established one remarkable 

 fact, namely, that old filters were better than new ones. 



The thanks of the meeting were presented to Mr. Bell. 



Mr. Slack then read a communication from Lieut.-Col. Dr. Wood- 

 ward " On the Structure of the Podui-a Scale, and certain other Test- 

 objects, and of their Eepresentation by Photo-micrography." 



Dr. Pigott said he should be very glad if this vexed question of 

 the Podura markings could be agreed upon in some way ; it had been 

 such a valuable scale in the construction of object-glasses that it could 

 not be prized too much. He would say, in reference to Dr. Woodward's 

 remarks, that before anyone depended upon the photograph of an 

 object as indicating real structure, they should be intimately acquainted 

 with its various aspects under the microscope, and decide which could 

 be relied upon. In photographing any object, the operator should 

 remember that the photographic lines show the actinic rays which 

 appear at the moment, and if the photographs were to give unbiassed 

 evidence they ought to be made under every possible condition of 

 focussing and correction. Dr. Woodward does not appear to have 

 borne this sufficiently in mind. He was, nevertheless, extremely 

 obliged to liim for his paper, for, having placed himself at the head of 

 photographic science in reference to the microscope, it was satisfactory 

 to know that he had brought his great practical power to bear on the 

 solution of this subject. 



The thanks of the meeting were given to Dr. Woodward. 



The President then said : The honour which the Society had 

 conferred upon him by their election of him to the chair was quite 

 unexpected. He was not a professed microscopist, but a microscopic 

 observer, and one who felt very thankful to the ingenious and talented 

 men who from time to time had made improvements in the instrument. 

 He thanked the Fellows for his election, and should take great plea- 

 sure in rendering the Society any service that lay in his power. His 

 first visit to a scientific society was made to the Microscopical, 

 eighteen years ago, and for years he had attended its meetings until 

 allured therefrom chiefly by his devotion to the study of a gigantic 

 form of boatbill {Balaniceps) which had been brought over to this 

 country. He had also worked largely at the Foraminifera. He had 

 intended that evening, if time had permitted, to read a short paper 

 illustrating the use of the microscope in developing the embryology of 



