62 THE AMERICAN MONTHLY [Feb 



the tip of the fing-er, projecting- as it does above the sur- 

 face, admits of an ordinary mounted needle being- drawn 

 quickly across its surface. The needle is then, with a cir- 

 cular motion, swept over the surface of a cover-g^lass held 

 between the thumb and fing-er of the left hand. With a 

 little practice, this method g-iv-es very satisfactory results, 

 quite an even spread, and the corpucles are very little dis- 

 torted. Necessarily in blood measurements, this latter is 

 of the utmost importance. — Harold N. Moyer. 



Drilling Lenses. — Make a lubricant with 1-2 drachm 

 aqua ammonia, 1 1-2 drachm sulphuric ether, 1-2 oz. g-um 

 camphor, 1 oz. spirits turpentine. Keep it corked and in 

 a low g-lass stopped bottle. The drill must be of steel as 

 hard as file steel 2 1-2 m. m, in dia. by 4 cm. long-. Fit it 

 in a handle of rubber with loose cap screw. Grind an oval 

 head entirely around the piece of steel, heat it red and 

 plung-e in cold water, g-rind the head on two sides fiat but 

 without drawing- the temper at all. Stroke on an oil-stone 

 to give a sharp finished point, rotating- it while stroking-. 

 Hold the lens or g-lass with the left hand with the point to 

 be drilled on a rounded knob of wood or cork securely 

 anchored. Keep the pariscopic side down. Drill half 

 throug-h and then turn and drill opposite. Hold the screw 

 driver between thumb and second fing-er. Put the index 

 fing-er in the revolving- cap. Dip in the lubricating- solu-. 

 tion as required. The first hole may be enlarg-ed by a 

 round file moistened with the same lubricant. Watch 

 crystals, plate g-lass, or any other g-lass may be drilled in 

 like manner. 



HEDICAL MICROSCOPY. 



Inflammation. — In man, it is characterized by four cardi- 

 nal symptoms ; redness,swelling-,heat,pain. But in the frog- 

 heat is lacking-. Virchow held that the essence of inflam- 

 mation was action of tissue cells. Acted upon by some 

 irritation, they beg-an to proliferate or multiply by division, 

 thereby producing- new material. 



Cohnheim observed under the microscope what took 



