44 



THE AMERICAN MONTHLY 



[March, 



find invaluable aid in the articles on 

 ' Staining Tissues in Microscopy ' 

 which Prof. Seaman has translated 

 for the journal. — Ed.] 



All vegetable sections, and some 

 leaves, may be prepared for staining 

 by soaking them in alcohol, or in a 

 mixture of dilute nitric acid and 

 chlorate of potash ; but I much pi'e- 

 fer the results obtained by first 

 bleaching them in ' Labarraque's so- 

 lution of chlorinated soda,' and then 

 treating them with alcohol for a few 

 hours. In half an ounce of the soda 

 solution a large number of sections 

 may be placed, but not more than a 

 dozen half or one-inch leaves, or 

 parts of large leaves cut into inch 

 pieces. Leaves in greater number 

 adhere to each other, and thereby 

 take longer to bleach. 



Sections of matured wood should 

 be kept in this solution from twelve 

 to eighteen hours ; sections of stems, 

 leaves, and petals from six to eighteen 

 hours ; pistils and stamens, and sec- 

 tions through the gynaecium and re- 

 ceptacle of flowers, from two to six 

 hours. 



Leaves and petals should not only 

 be bleached by the Labarraque, but 

 should also be rendered translucent. 

 This is accomplished in from six 

 hours to six days. 



If delicate leaves show evidence of 

 disintegration after they are bleached, 

 but before they have become translu- 

 cent, they should be removed to al- 

 cohol, after washing them in water 

 as described below. This renders 

 them translucent within two davs. 



After removing from the Labar- 

 raque, put them into half a pint of 

 clear water. Change the water five 

 times during twenty-four hours, acid- 

 ulating the third washing with five 

 or ten drops of nitric acid. Sections 

 can be washed in half the time re- 

 quired for leaves. 



Next, put into alcohol, which in a 

 few hours prepares them for stain- 

 ing. 



In alcohol, tissue may be kept for 

 months without turning yellow. 



I. — STAINING LEAVES AND PETALS. 



For staining leaves and petals the 

 best dyes are anilin blue and hEsma- 

 toxylin. 



Other anilins than the blue may 

 be used, but they are not so pleasant 

 to the eye, and are harder to work, 

 as they fade out in both alcohol and 

 oil of cloves. 



Red anilin may be used, one quar- 

 ter of a grain to an ounce of alcohol ; 

 violet, one-half grain ; and green, 

 three grains. 



To make the blue anilin dye, dis- 

 solve in a mortar half a grain of 

 ' Nicholson's soluble blue pure ' in 

 one ounce of 90-93 per cent, alcohol, 

 which has been acidulated with half 

 a drop of nitric acid ; then filter. 



Dilute a portion of this with alco- 

 hol to obtain a quailer-grain solution. 



The formula for the hematoxylin 

 dye is given further on. 



A bright purple dye, good for 

 leaves and sections, is made by steep- 

 ing fresh berries of the Phytolacca 

 decandra in alcohol. The stainings 

 are quite permanent, but the dye 

 does not keep over six weeks. 

 To St a hi Leaves and Petals in 

 Anilin Blue. 



1st. Transfer several small leaves 

 from alcohol to about half a drachm 

 of the quarter-grain blue. 



If not stained of sufiicient depth of 

 hue in one hour — 



2d. Transfer to the half-grain blue 

 for a quarter or half-hour. 



3d. Brush in 93 per cent, alcohol 

 with camel-hair pencil, and trim the 

 edges of cut leaves. Any excess of 

 color may be soaked out in this di- 

 lute alcohol. 



4th. Put into half a drachm of ab- 

 solute alcohol for half or one hour. 

 In this but a trace of color will be lost. 



t;th. Put in oil of cloves for one 

 hovu", or until ready to mount in Can- 

 ada balsam and benzole. 

 Po Stain P eaves and Petals in 

 Hcematoxylin . 



I St. Transfer from alcohol to water 

 for five minutes. 



