Dec. 1, 1869.] 



HAKDWICKE'S S CIENCE- GOSSIP. 



281 



MICROSCOPY. 



Cells. — The new cell is a very old acquaintance 

 of mine, and a very untrustworthy one. I would 

 strongly advise your readers never to use india- 

 rubber bands, as they always shrink away from the 

 glass even if coated with Brunswick black. Bruns- 

 wick black and gold size, both become porous with 

 age, thereby allowing liquid preparations to leak, 

 and both " sweat," i.e., condense in oily drops on 

 the covering glass of dry preparations. I have 

 tried a great many kinds of cells, and I think jlat 

 brass rings the ,best. As a cement, Bell's is pro- 

 bably the best ; it seems always to retain a small 

 amount of elasticity, and does not "jar" off the 

 slide. It has, however, one drawback, viz., that 

 succeeding coats re-dissolve the first, but with 

 a wire clip, this is of little importance. — C. P. 

 Smith. 



Prickly Pear. — I have found an interesting 

 object in the^Prickly Pear, or Indian Pig, now in 

 season in our markets. The spines, although very 

 minute, are easily extracted from the free end of the 

 fruit by means of the forceps, and, when viewed by 

 reflected light, present a beautiful and remarkable 

 appearance. The observer will see the cause of the 

 extraordinary sensation in the lips succeeding an 

 incautious bite of the so-called pear. Its pulp 

 contains a multitude of beautiful raphides, which, 

 however, do not appear to be affected by polarized 

 light, and the stomata and curious star-like bodies 

 of the cuticle also make a very effective slide. — 

 G. W. 



India-rubber Cells. — As Mr. Wonfor so com- 

 pletely denounces the use of the India-rubber cells, 

 I trust I may be allowed to make a few remarks on 

 his statement in regard to them. In justice to my- 

 self I may state that had I not been thoroughly 

 convinced of the efficiency of the cell described, I 

 should not have ventured to have asked for space 

 in your valuable columns to describe a cell which, 

 according to your correspondent, would turn out 

 so completely useless. That it is one of the cheapest 

 and most efficient cells, I am still firmly convinced, 

 notwithstanding the remarks of your correspondent, 

 and I base my belief on the following grounds. I 

 have a large number of cells bearing on their labels 

 the dates 1864, '65, '66 ; these are in as good con- 

 dition as when I first constructed them, and are 

 likely to remain so, for what with travelling, &c, 

 they have met with as rough usage as the majority 

 of slides could experience. Selecting a few of the 

 less valuable ones, I experimented on them, allow 

 ing them to fall from a good height on to a table on 

 the fiat of the glass, and striking them sharply on 

 the edge, — in fact, submitting them to forces which 

 the most careless microscopist could guard his 

 collection from ; and what was the result ? Not the 



slightest flaw in the union of the cell components 

 was detected, and I have a higher opinion of their 

 durability than ever I had before. My friend who 

 first showed me this method has had a far older 

 experience than myself, and he still prefers it to any 

 other cell. Besides, I must remind Mr. Wonfor 

 that every careful microscopist keeps his slides 

 bracketed or otherwise disposed so that the jars 

 they are subject to are very insignificant. The force 

 I used in experimenting was far too violent for a/air 

 test. — W. B. Lewis. 



Pish Scales. — The illustration now given in 

 continuation of the series of fish scales is that of 



Fig. '250. Scale of Trout {Suimo trutta). 



the Common Trout {Salmo trutta), from specimens 

 identified and kindly furnished by Henry Lee, Esq., 

 P.L.S. 



Leamington Microscopical Society. — We are 

 glad to learn of the establishment of a Microscopical 

 Society at Leamington, and wish it success. 



Microscopical Manipulation. — The publica- 

 tion of Mr. Suffolk's Lectures was commenced in 

 the Chemical News, in No. 513, September 24, and 

 continued weekly. We also observe that they are 

 being reproduced in the English Mechanic. 



Melicerta in Pamilies. — It may be new to 

 most, and interesting to all, microscopists, to know 

 that these beautiful rotifera are sometimes seen 

 grouped together. I have now in my tank a family 

 of four attached in a dendritic manner. Two in 

 this polype form are very numerous in my aquarium. 

 —G. H. F., 13, West Abbey Road, N.W. 



Vulcanite Cells are recommended by some 

 of our correspondents, but their communications 

 arrived too late for insertion. 



