122 . PHOCEEDINGS OF THE SOCIETY". 



Mr. Charles F. Rousselet's communication, " Fifth List of New 

 Rotifers since 1.S95," was read in abstract by Dr. Eyre, as the author 

 was suffering from laryngitis. 



The Chairman thanked Mr. Rousselet on behalf of the Society for 

 this further addition to the list of the Rotifera, and trusted that some 

 day he might be induced to bring out a monograph on the subject. 

 The vote of thanks was carried with acclamation. 



The Secretary then read a short communication from Dr. Marshall 

 Ewell, P'.R.M.S., on " A New Micrometer" (with sketch). 



The Chairman stated that the note would duly appear in the Journal, 

 and he had no doubt it would be found a useful communication. He 

 thought the Society would wish to thank Dr. Marshall Ewell for having 

 sent it. 



A vote of thanks was then carried with .acclamation. 



The Chairman then requested Mr. J. B. Barnard, F.R.M.S.. to 



demonstrate the apparatus for " The Employment of Ultra-violet Light 

 in Microscopy." Whilst doing so, Mr. Barnard illustrated some of the 

 results obtained by this method by means of lantern-slides. 



The Chairman remarked that Mr. Barnard's work was just the type 

 most welcomed in the Society, and felt sure Mr. Barnard would agree that 

 when the method had been longer in use in the hands of experts like 

 liimself. it would probably yield very much more important results than 

 those shown during the evening. 



Mr. Maurice Blood said he would like to ask Mr. Barnard one 

 question. He presumed these lenses were corrected for one particular 

 wave-length of ultra-violet light, and they could not be used for accurate 

 work with any other. As a matter of curiosity, he would like to ask 

 him what was the wave-length of the mercury line which he used for 

 focussing ? 



Dr. Eyre congratulated Mr. Barnard on the results already obtained. 

 Bacteria when examined by ordinary methods appeared to have no 

 internal structure, although it had always been believed that in time the 

 presence of nuclei would be demonstrated. Mr. Barnard's photographs 

 showed indications of structure inside the cell-envelopes which might 

 well be nuclear. The question arose, however, whether tbe cell- 

 membrane had undergone some distortion in Mr. Barnard's preparations 

 as a result of plasmolysis or similar phenomena. The Society was very 

 much indebted to Mr. Barnard, because his was the kind of communica- 

 tion wanted, real live work pointing out the directions in which advances 

 were needed. 



The cordial thanks of the meeting were accorded to Mr. Barnard for 

 his paper. 



Mr. Barnard, in reply to Mr. Blood, said the objectives were corrected 

 for the cadmium line primarily. The computation was made on that 

 wave-length. They worked equally well, and in some respects were 

 easier to use, with magnesium electrodes. The cadmium line was 27.") /a, 

 a difference of only 8 /a in the wave-length. There was considerably 



