156 THE AMERICAN MONTHLY [Sept 



visible. When the doctor reluctantly admitted his fail- 

 ure, the wife took a small particle of the blood, placed it 

 a short distance from the center of the slip then tightly 

 drew a smooth edged slip with a firm motion over tie 

 slip containing the small particle of blood, covered and 

 examined when a beautiful picture of red corpuscles and 

 white corpuscles was presented to view. 



The Use of a Blue Glass Between the Source of 

 Illumination and the Objective. — In artificial colors, 

 white light is composed of three primary colors, blue, 

 red and yellow. This is not true of sunlight theprimar-y 

 or fundamental colors of which arc composed of red, green 

 and violet. Our lamps generally emit a more or less 

 reddish, yellow light. To correct this, use a piece of the 

 proper blue glass obtained for the purpose from a mi- 

 croscopic dealer. The blue adds the other primary and 

 makes the light practically white. After becoming 

 accustomed to the blue glass it will be very uncomfort- 

 able to use the microscope without its aid. 



Flower Crystallizations of Sugar. — By the follow- 

 ing method one will never fail in producing these crys- 

 talls. Take any white sugar and in one test-tube make 

 a saturated solution in water and in one tube a saturated 

 solution in alcohol. Mix the two in a third test tube, 

 when thoroughly mixed place a drop of the mixture on 

 the center of a glass slip. The sugar will harden into an 

 amorphous mass. When the mass has hardened, place 

 the slip on the shade of a student's lamp. The crystals 

 will soon begin to form. Leave the slip on the shade 

 until they have formed throughout the mass and then 

 remove and mount in balsam. Piso's Cough Cure placed 

 upon a slip, hardened and set upon the lamp shade will 

 produce the crystals. The hardened mass on the slip, 

 placed in a damp cellar or cupboard will produce the 

 crystalization in the course of twenty-four hours. 



