165 



very interesting paper, and that this new piece of apparatus would be in- 

 valuable to all who did not cut sections by hand. There could be no doubt 

 whatever as to the greater value of sections cut from fresh material in 

 comparison with those which had been kept for some time hardening, and 

 he thought that a fresh specimen of a morbid or animal tissue would un- 

 doubtedly be more likely to give accurate details to the observer than one 

 which had been for weeks hardening in chromic acid. Dr. Pritchard's 

 freezing microtome was certainly good ; but there were many persons who 

 could not cut sections by hand, and therefore required an assistance of this 

 kind, and of all that he had seen this one appeared to be decidedly the 

 simplest. For his own part he preferred to cut sections by hand, but he was 

 quite aware that many persons found it difficult to do so ; he was, however, 

 strongly in favour of the plan of freezing as a means of hardening fresh 

 specimens. It was very hard to have to wait three weeks for a morbid 

 specimen to harden before it could be cut, and at the end of that time to 

 find that it had undergone distortion ; for although some of the advocates of 

 re-agents would say there was no distortion, he knew from experience that 

 there were very often alterations on account of contraction, and he could 

 briug specimens cut both before and after hardening which would clearly 

 show that such was the case. He should like to ask Mr. Williams if he had 

 any experience in the use of ether spray for freezing, in the place of ice and 

 salt ? Some had recommended it, but it seemed to him to be an expensive 

 and somewhat disagreeable substitute. 



Mr. Williams said of course there were many freezing mixtures, but he 

 did not think that there were any so effective or so cheap as ice and salt. 



The Chairman announced that Mr. Williams had promised to give them a 

 demonstration on the use of the microtome at their Gossip night in March. 

 A vote of thanks to Mr. Williams for his paper was unanimously 

 carried. 



Mr. A. Cottam read a paper " On Aulacodiscus Africanus, a new Diatom 

 from West Africa," illustrating the subject by a number of beautifully 

 executed drawings. 



The Chairman said that as he had not gone very much into this subject he 

 could hardly express an opinion upon it, but he felt sure that all who had 

 heard the paper would join with him in giving a hearty vote of thanks to 

 Mr. Cottam for bringing the subject before them. 



The thanks of the Club were voted to Mr. Cottam for his paper. 

 Mr. N. E. Green read a paper " On a New Stage Arrangement for Exa- 

 mining Objects by Reflected or Transmitted Light." The subject was illus- 

 trated by pencil drawings of the appearances described in the paper, and by 

 the exhibition of objects under microscopes in the room. 



The Chairman asked for a vote of thanks to Mr. Green for his very 

 interesting paper, and also for his exhibition of the specimens. Some time 

 ago Mr. Green gave them a beautiful demonstration of the illumination of 

 objects by the lime light, and this would doubtless be remembered with 

 great pleasure by all who were then present. Before he sat down he wished 

 to advert for a moment to the noticeable absence of their President — for he 



