936 PKOCEEDINGS OF THE SOCIETY. 



Mr. Michael said he had been in the habit of using practically the 

 same fluid for some years, and could say from experience that it 

 was a most excellent preservative fluid, and also a very good mounting 

 fluid when used of various strengths, according to the requirements of 

 the objects to be mounted. If the glycerine was present in any great 

 quantity it certainly had a decalcifying effect, and he should hesitate 

 to use it for some objects. As to the cell material, he had occasionally 

 used a similar cement, and though he had not used it largely he had 

 found it very good so far. 



Dr. Matthews said that in finishing cells a very good preventive 

 against the oozing out of the fluid was a small strip of the thinnest 

 tinfoil, painted on one side with gold size, and whilst still " tacky," 

 applied over the junction between the cell and the cover. When this 

 was smoothed down — and it could be done so effectually that it could 

 scarcely be felt afterwards — the result was a perfectly tight connec- 

 tion which could not possibly leak. He might also mention a 

 manner of filling cells with fluid without the possibility of getting any 

 air bubbles inside. It was to have a small trough or cell large enough 

 to allow an ordinary slide to be placed inside it with the cell attached 

 in the usual way, the fluid was then poured into this trough until it 

 filled up to a point a little higher than the top of the cell on the slide. 

 If the object was then placed in the cell and the cover put on, there 

 was no chance whatever of a bubble being included. 



Mr. Lovett said he had now an experience of three or four years, 

 but had not found any change of form to take place in the objects 

 where j)roper precautions had been taken in mounting. If very dense 

 fluid was used, it would of course be prejudicial to some objects ; but 

 if prepared in dense fluid and mounted in light, there would be no 

 difficulty. It was important to have the materials good in quality and 

 properly mixed ; the best way was to get them prepared by a good 

 chemist, and it was then very easy to mix them with the gold size. 

 As regarded shellac, he thought it would not do at all for anything 

 containing alcohol. The solution he had recommended would have 

 an effect on calcareous objects if it was too strong ; but in the weak 

 form he had mentioned, it would be found to have no disadvantage. He 

 had found bubbles in some cells which had been securely fastened 

 down, but he was inclined to regard them as vacuum bubbles, because 

 if they had been air bubbles some of the fluid must necessarily have 

 got out to let the air get in. This cement was so perfectly proof against 

 the action of alcohol, that he had used it successfully to stop the leak- 

 ing of some spirit casks. When an air bubble was caused by the 

 cover being pressed down on the cell so much as to let some of the 

 fluid get out, it could be got rid of by pressing it out at the place 

 where the fluid had leaked and letting the fluid run back again when 

 the pressure was removed, and where there had been any leakage the 

 cement would stop it at once. 



