PROCEEDINGS OF THE SOCIETY. 219 



variation. Much work had been done in this way, e.g., the cultivation 

 of diatoms and other algie in or on various media. In connexion 

 with the cultivation of diatoms the work of Dr. Allen, althouEfh dealina: 

 with marine forms, was p.irticularly referred to. Dr. Allen found that 

 in artificial sea- water the diatoms would not thrive, whereas if an extremely 

 small amount of actual sea-water was added they developed quite readily. 

 The explanation seemed to be that there was some unknown substance, 

 probably organic in origin and possibly comparable to the so-called 

 vitamines, present in ordinary sea-water which was essential to the proper 

 growth of the diatoms. The same might very well be done for fresh- 

 water organisms, and it would be very important if this matter could be 

 further investigated. Another case specially referred to as showing the 

 effect of particular kinds of food on structure was that of Prof. Agar's 

 curiously modified forms of Simocephalus, due apparently to their 

 being reared on a particular species of Oklamydomas. 



Another line of experimental work was in connexion with problems 

 of heredity, and Prof. Agar's results with Daphnia and Simocephalus, 

 and Prof. Punnett's with Hydatlna, were mentioned in illustration of 

 this kind of work. 



Yet another way in which living pond-life organisms lent themselves 

 to the expeiimental method was as subjects for intra-vitam staining. 

 Prof. Fischel's results with Daphnia were quoted as a good illustration 

 of what might be undertaken in this direction. 



xiltogether it was evident that pond-life organisms offered a wide 

 field for experimental biological work, and it was to be hoped that many 

 already familiar with particular groups from the systematic and morpho- 

 logical standpoints would be induced to give some attention to the pos- 

 sibilities for experimental biological work which such organisms afforded. 



Mr. Scourfield then called attention in detail to many of the exhibits, 

 which he thought were more varied and certainly more numerous than 

 had been the case for several years past. 



On the motion of the President, a hearty vote of thanks was 

 accorded to the jMembers of the Quekett Microscopical Clul), and to the 

 Fellows of the Royal Microscopical Society who had kindly exhibited 

 specimens, and to Mi. Scourfield for his remarks. 



The President announced that the next meeting would be held on 

 June 15 ; that the Biological Section would meet on June 1, when Mr. 

 F. Martin Duncan would make a communication on " Studies in Insect 

 Biology " ; that the members of the Biological Section, by the invitation 

 of the President, would pay a visit to the Bacteriological Laboratories 

 at Guy's Hospital on June 8 ; and that the Leather Industries Section 

 would meet on May 25, when Mr, Percy Hampshire would make a 

 communication on " ' Run ' Pelts in Sweating Process of De-wooling." 



The following Objects were exhibited : — 

 Mr, S, C, Akehurst . . Larva of Gorethra plumicomis, showing air 



sacs with polarized light. 

 Mr. A. J. Bowtell . . Larva of Gnat. 



Miss M. H. Brooks, , Stephanoceros eichhornii. 



Canon G. R. BuUock-AVebster Nitella mucronata, showing cyclosis. 

 Mr. C. H. Caflfyn . . Newly hatched hvvee of Tanyjms. 



Mr. W. R. Chappie . , Young larva of Corethra plumlcornls. 



