260 PROCEEDINGS OF THE SOCIETY. 



could only lead to barren contradiction. There was therefore only one 

 matter for him to deal with, namely Mr. Conrady's experiment exhibited 

 that evening, with the object of showing that however he illuminated 

 his grating he could not get rid of the spectra. He pointed out that 

 Mr. Conrady's apparatus was not properly set up for testing this point. 

 Fellows would have observed in his photographs that he (Mr, Gordon) 

 did not start observing the spectra until the source of light had been 

 brought within about ^^^ in. of the grating, and the spectrum did not 

 change to the spectrum of a single opening until the source of light was 

 brought to within -^^ in. of the grating. Now Mr. Conrady's source of 

 liglit was a lamp flame arranged " end on " in front of the condenser, 

 and it was impossible to place an image of such an object at ^-^ in. 

 from the grating, for the image would have a greater depth than that 

 measured along the optical axis, and when one edge of it was actually 

 in the grating the other edge would be far enough away to give visible 

 spectra in the tube of the instrument. It was impossible to draw any 

 inferences at all from such an experiment. Mr. Gordon on the contrary 

 had availed himself of the slit which Professor Abbe himself prescribed 

 as the source of light in these Abbe experiments, and so obtained what 

 might be termed a film source of light which could be placed with great 

 precision in any determined position. That was why he had succeeded 

 where Mr. Conrady had failed. 



The Secretary said they had two other papers on the agenda for the 

 evening, one V)y Mr. James Murray, " On some Tardigrada from the 

 Sikkim Himalaya," and the other by Dr. Eugene Penard, " On some 

 Rhizopods from the Sikkim Himalaya." Mr. Rousselet, who had been 

 unfortunately taken suddenly ill, was to have communicated these 

 papers, l>ut in his absence, as they consisted largely of descriptions of 

 species, it was decided to take these papers as read. Mr. Penard's paper 

 described what had been found in the district named, at about 3<i00 ft. 

 above sea level, whilst Mr. Murray's paper gave a description of a 

 number of species of Tardigrada found chiefly in moss from the same 

 region, and concluded with a list of the literature of the subject. 



The President said that papers of this kind were no doubt extremely 

 useful as additions to zoological knowledge of these organisms, but they 

 did not usually lend themselves to much discussion. 



The thanks of the Society were unanimously voted to the authors of 

 the several papers. 



Dr. Hebb said he had received a letter from Mr. E. M. Nelson 

 which was an appendix to his paper on the flagella of the tubercle 

 bacillus : — 



" There was a young doctor (Cambridge) here who wanted to see 

 the flagella of tubercle. So we went at it, and he could make nothing 

 of it at all. I then got him to put down his pipe, and kept him in a 

 darkened room for a couple of hours. After this he began to see some- 

 thing, and as time went on he saw them more readily. After a little he 

 was able to see them without difficulty, and then took to finding fresh 

 examples all over the slide. I inclose some sketches he made. I am 



