94 THE AMERICAN MONTHLY [May, 



add a drop of glycerin, and cover. Place a clip on the cover, and hold the 

 slip for an instant under a stream of cold water. Dry the slip carefully with 

 a soft linen handkerchief, and give the amount a thin ring of zinc white 

 cement. The slide may be now examined under the microscope. The nu- 

 cleus with its plexus of fibrils is stained red, the peri-nuclear part yellow. On 

 the third, fifth, and seventh days after mounting, ring the slide with gold size, 

 and finally finish off with zinc white. Such a preparation, if not absolutely 

 permanent, will keep for many years without change. The object of first 

 treating the blood with picric acid is to coagulate the contents of the corpus- 

 cles ; and if osmic acid be used for this purpose, instead of picric acid, and the 

 blood be afterwards stained with picro-carmine. or logwood, the preparation 

 will show colorless corpuscles with their nuclei stained. 



PICRO-CARMINE AND LOGWOOD. 



This combination may be employed for sections of tongue, skin, striped 

 muscle and many other tissues. Dr. Gibbes states that he has found it 

 ' useful in bringing out the delicate tissue in the tubuli seminiferi of the 

 testis, and showing the developing spermatozoa there.' 



Stain the sections for twenty-four hours with picro-carmine and then, 

 without rinsing them, transfer to a weak logwood solution until they assume 

 a violet color ; they are then gently washed in water and mounted in glyc- 

 erin or balsam. 



PICRO-CARMINE ROSEIN AND IODINE GREEN. 



I have used this combination for some time for staining odontophores, and 

 the result !s beautiful in the extreme. 



The palate is first stained with picro-carmine for twenty-four hours ; it is 

 then transferred for a few minutes to a i% solution of rosein in rectified spirit ; 

 from this it is removed to 9o"b alcohol, to remove the surplus color, and 

 then it is stained with a i% alcoholic solution of iodine green. It is next 

 washed in alcohol, cleared in clove oil, and mounted in Canada balsam. 



CARMINE, AND INDIGO-CARMINE. 



For sections of skin and scalp, this combination is certainly the best I have 

 ever employed. 



Stain the sections with carmine, and rinse them rapidly in rectified spirit, 

 acidulated with a little hydrochloric acid ; wash all traces of the acid awav 

 with spirit, and transfer them to the indigo-carmine solution, which is pre- 

 pared as follows : — Make a saturated aqueous solution of indigo-carmine or 

 sulpindigotate of soda, and allow it to stand for an hour; then add to it, 

 slowly and gently, about one-third its bulk of rectified spirit; syphon ofl'the 

 mixture from the precipitate and pass it through several folds of fine filtering 

 paper ; it is then ready for use. The sections soon stain in this, and should 

 therefore be examined every few minutes to avoid over staining ; when ready 

 they are rinsed in 6o"o of alcohol, dehydrated, cleared in clove oil, and mounted 

 in balsam. 



LOGWOOD AND EOSIN. 



This is a beautiful combination for cartilage and the cerebellum. The 

 sections are first stained with logwood, and are then washed ; they are next 

 stained for about one minute with a strong solution of eosin (I prefer an al- 

 coholic solution for this purpose) , and are finally washed in rectified spirit, 

 dehydrated, cleared and mounted in Canada balsam. 



PICRO-CARMINE AND IODINE GREEN. 



This combination may be employed for sections of tongue, stomach, and 

 oesophagus. Stain the sections first with picro-carmine, and wash them in 



