428 SUMMARY OF CURRENT RESEARCHES RELATING TO 



matter from the corpuscles by the action of water, and to place 

 some of the solution of haemoglobin thus obtained, under a cover- 

 glass (which should be raised at one side by a slip of glass laid 

 beneath it) adding some pyrogallic acid. Frog's blood, the colouring 

 matter of which is very difficult to extract, must remain in a moist 

 chamber for several days before the acid is applied ; the crystals then 

 appear within the corpuscles. (KoUiker has seen them similarly in 

 the red corpuscles of Perea fluviaidis.) It usually requires several 

 hours' treatment to produce the crystals ; they will keep for some time 

 in the fluid. 



Preserving Flowers.* — For preserving the colours of parts of 

 flowers which it is desired to mount for the Microscope, Mr. G. Stocker 

 finds a saturated solution of the ordinary potash alum crystallized 

 (AI2 3SO4, K2 SO4, 24 HoO) most excellent. The objects should 

 remain in the liquid for ten minutes or so, and then be dried between 

 bibulous paper, placed in turpentine to render them transparent, and 

 mounted in balsam. A portion of the vexillum of TJlex Europceus so 

 mounted is without any of that reddishness which accompanies speci- 

 mens mounted in the ordinary way ; and a stigma of Crocus aativus is 

 as full of colour as in its original state. 



Cleaning Diatoms.t —Mr. K. M. Cunningham makes the following 

 suggestion for cleaning diatomaceous material when largely con- 

 taminated with sand. " A quantity of the material is placed in a 

 teaspoon, and water is then added until the teaspoon is nearly filled ; 

 the spoon is gently shaken with a back and forth or a circular motion, 

 for a few seconds or longer, when the water must be quickly drawn 

 off by applying the tip of a finger to the point of the spoon, taking 

 care to draw off the superficial water, without allowing the heavier 

 sediment to pass over the point. Pour from the spoon into a watch- 

 glass, the surplus water is then drained off, and the diatoms removed 

 for mounting. This method produces a magical concentration of the 

 diatoms, large and small, making the remaining sand inconspicuous 

 by the superabundance of the diatoms." 



Gaule's Method of Imbedding. | — The following method of im- 

 bedding was worked out by Dr. J. Gaule, by whom it was com- 

 municated to Professor E. A. Birge, who, having tried it on all sorts 

 of tissue, can fully recommend it. 



" A piece of tissue of convenient size is to be taken, treated with 

 the ordinary reagents, and stained in the mass. If large it may be 

 convenient to remove it from the staining fluid to alcohol for a few 

 hours and then replace it. When thoroughly stained, the specimen 

 is to be put in 70 per cent, alcohol for about twelve hours, then 

 transferred to absolute alcohol until it is completely dehydrated. 

 Then put it in oil of cloves overnight, or leave it there until it is 

 convenient to imbed it. Place it in turpentine half an hour — large 



• Sci.-Gossip, 1882, pp. 65-6. 



t Amer. Mon. Mior. Joiirn., iii. (1882; p. 14. 



I Ibifl.. pp. 73-5. 



