87 



Mr. Mackenzie said he had used this apparatus for the last fortnight, and 

 found it to work admirably, so that he was able to resolve many of the 

 more difficult diatoms. At first he made the illuminator adhere by a little 

 water, after that he made a clip to keep it on, but since then he had found 

 the best plan was to secure it by means of a small slip of ebonite. He did 

 not much like the plan of fixing the illuminator to the substage, because in 

 moving it about to find another object the film of water was apt to become 

 broken. 



Mr Curties thought that this difficulty would not occur if oil were used. 



Mr. Mackenzie said he had tried oil also. 



Dr. Matthews enquii-ed what oil Mr. Curties used for the purpose ? 



Mr, Curties said he used castor oil. The object in attaching the illumi- 

 nator to the substage was to avail oneself of all the movemc' ts of the sub- 

 stage, and it must certainly be of advantage as to adjustments to have it 

 attached to that part of the instrument which possessed them. Many 

 instruments had stages so thick as to prevent the use of rays of such 

 obliquity as could otherwise be used. 



Mr Ingpen said that the greatest angle likely to be wanted was 45^. 

 Yery few wanted more. If they had this super stage they must have 

 something in the shape of a prism or bull's-eye to reflect the light, because 

 if they took it from below the stage they would get it at a greater angle 

 than they could use. 



Mr. Curties said that it was certainly a piece of apparatus of great 

 value, and one that could be fitted to almost any microscope. 



Mr. T. C. White made a communication " On the Resting Spores of Pro- 

 tococcus pluvialisJ' 



The President in inviting discussion upon the subject remarked that the 

 great difficulty in following up such observations was the time required for 

 tracing out all the changes. Few, if any, amongst the members could do 

 as Mr. Dallinger had done. 



The thanks of the meeting were voted to Mr. White for his paper. 



Dr. Horatio Whittell read a highly interesting paper " On the Association 

 of Bodies resembling Psorosjpermice with the degeneration of Hydatid 

 Cysts." 



The President said he was extremely glad that Dr. Whittell had brought 

 this subject forward. Allusion had been made in the paper to a micro- 

 scopic Haematozoon, a description of which was forwarded to him by Dr. 

 Whittell. From this and from the figure sent with it, he was at the time 

 led to believe that it might be the larva of Filaria sanguinis hominis. 

 He had now, however, looked at the specimen carefully, and had satisfied 

 himself that it was not a Nematoid structure, but some foreign body. The 

 integument was absent, and it did not correspond either in size, appearance 

 or measurement with the worm in question. The largest in size of the 

 Filarice did not exceed l-125in., whereas this object was nearly l-40in. 

 Dr. Whittell's paper dealt with two distinct subjects — fircst with Hydatids 

 and next with the formation of something else within Hydatids. He had 

 mentioned that he had observed cilia in or upon the Echinococci. This was 



