248 THE MICROSCOPE. 



crystallizes, and if formed out of strong acid, very mucb 

 resembles that of the crystals of uric acid ; when mixed 

 up with other forms, long dagger-like or lancet-shaped 

 crystals are seen, which might well deceive. 



We may also notice in this place what Majendie pointed 

 out, that in certain albuminous mixtures, iodine loses the 

 property of colouring starch blue. This difficulty must be 

 got rid of before iodine can be said to be an infallible test 

 in micro-chemistry. 



Collecting Objects. — Mr. G. Shadbolt contributes the fol- 

 lowing useful hints for collecting objects for microscopical 

 examination : — 



" Rivers, brooks, springs, fountains, ponds, marshes^ 

 bogs, and rocks by the sea-side, are all localities that may 

 be expected to be productive; some being more prolific 

 than others, and the species obtained differing, of course, 

 in general, to a certain extent, according to the habitat. 

 On considering the nature of some of the places indicated, 

 it will be apparent that, in order to spend a day in col- 

 lecting with any comfort, it will be necessary to make 

 some provision for keeping the feet dry, for which a pair 

 of India-rubber goloshes will answer, or better still, a pair 

 of waterproof fishing-boots; but without one or other the 

 work is by no means pleasant. 



" A dozen or two of small bottles made of glass-tubing, 

 about half an inch in diameter, and without necks, and 

 from one to two inches in length, are the most convenient 

 depositories for the specimens, if intended ultimately foi 

 mounting; and it is advisable also to take two or three 

 wide-mouthed bottles of a larger size, holding from one to 

 two fluid-ounces, an old iron spoon, a tin box, some pieces 

 of linen or calico, two or three inches square, a piece of 

 string, a slip or two of glass, with the edges ground, such 

 as are used for mounting objects; and lastly, a good and 

 pretty powerful hand-magnifier. Two Coddiugton lenses, 

 mounted in one frame of about half an inch, and one-tenth 

 of an inch in focal power, are specially convenient. 



" Swanscombe Salt-marsh will be found well worth a 

 visit; and it can be reached by steam-boat or railway 

 from London-bridge to Northflcet. On quitting the rail- 

 way station, make towards the almshouses on the top of 



