218 THE AMERICAN MONTHLY [July, 



reduces the platinum and covers the tube with a layer of bright 

 metal. Placing the metalized tube in a bath of sulphate of cop- 

 per, and connecting the tube to the negative pole of a battery 

 of suitable energy, there is deposited on the platinum a ring of 

 copper. If the operation has been successful, the copper will 

 be malleable and very adhesive. In this state a glass tube 

 topped with copper can be treated like a genuine metallic tube 

 and soldered to iron, copper, bronze, platinum, etc. — Age of 

 Steel. 



Formaldehyde for Hardening. — Dr. W. M. Eccles compares 

 the hardening action of formic aldehyde on tissues with that of 

 the fluids in general use. Absolute alcohol hardens most tis- 

 sues in four or five days, but is apt to render them brittle or to 

 harden them very unequally. Methylated spirit requires four- 

 teen days. Chromic acid, with or without alcohol hardens in 

 seven days, but renders the tissues brittle. Potassium bichro- 

 mate in Muller's fluid requires six weeks and must be constantly 

 renewed. Mercury perchloride hardens rapidly and interferes 

 with subsequent staining. 



But in the case of formic aldehyde, very soft varieties of nor- 

 mal and pathological structures, the most difficult to prepare, 

 all can be well hardened in three days. None of the tissues 

 became brittle, all being cut easily with an ether-freezing micro- 

 tome after soaking in gum, and all staining well with logwood 

 and cosine. At the same time the cells are unaltered in char- 

 acter or shape. For very soft tissues, use a 40 per cent solution, 

 for harder ones, a 20 per cent solution will do, and for quite 

 firm material, 10 per cent will do. — Brit. Med. Jour. 



Writing upon Glass. — Take 2 parts shellac, 1 part Venice 

 turpentine, and dissolve them in the water bath in 3 parts of 

 oil of turpentine. After complete solution, 1 part lampblack 

 is added and the solution well stirred. 



MEDICAL MICROSCOPY. 



Blood of Melancholia. — A microscopical examination of 

 blood of twelve patients showed a marked diminution of glob- 

 ules and of hemoglobin. The administration of iron alone or 

 combined with quinine or strychnine increased their numbers 

 and produced corresponding improvement in the patients. 



