306 OOLGI BODIES ETC. 



(20 parts of saturated picric in absolute alcohol and 80 parts of 

 20 per cent, alcohol). The red stain begins to be extracted at 

 once. After half a minute examine under microscope. The 

 nuclei should be distinctly yellow, mitochondria still bright red. 

 If differentiation is nearly complete, transfer to a weaker picric 

 solution (as above, but only 10 parts of picric to 90 parts of 20 per 

 cent, alcohol), which slows down the action and enables it to be 

 watched more carefully. Wash in aq, dcst., then quickly into 70 

 per cent., 90 per cent, and to absolute alcohol (in which two 

 minutes), xylol, mount . 



695. Champy-Kull's Acid Fuchsin, Toluidin Blue and Aurantia 

 (KuLL, Anat. Anz., Bd. xlv, 1913). The following method, while 

 being generally useful, will be found very convenient for work on 

 Invertebrata. It gives results intermediate between those of 

 Benda and Altmann, but is shorter and undoubtedly better than 

 the method of Benda. It will be found very useful for embryo- 

 logical research, and probably also for protozoology. Fix in 

 Champy (§ 47) (we find Flemming-without-acetic acid will do, too) 

 for twenty-four hours. Pieces to be fixed must be small. After 

 fixation wash half an hour in aq. dest., and then transfer to a 

 mixture of 1 part acid acet. pyrolignosum rect., and 2 parts 1 per 

 cent, chromic acid, for twenty hours. Wash half an hour in aq. 

 dest., and transfer to a 3 per cent, solution of potassium bichromate 

 for three days. Wash under tap for twenty-four hours ; pass 

 through up-graded alcohols to xylol ; imbed in paraffin wax (or 

 celloidin method, if desired). Section 4 or 5 /x. Proceed as follows : 

 (1) Stain in Altmann's acid fuchsin anilin oil mixture (5 to 10 grm, 

 of acid fuchsin in 100 c.c. of anilin oil-water), and heat till steam- 

 ing. (2) Set slide aside to cool for six minutes (this is important), 

 pour off, and wash quickly in aq. dest. (3) Counter-stain in either 

 a 0-5 per cent, solution of toluidin blue or a saturated solution of 

 thionin in aq. dest. for one to two minutes. Wash in aq. dest. 

 In some cases the time in the blue stain must be shortened. 

 Transfer to a 0-5 per cent, solution of aurantia in 70 per cent, 

 alcohol for from twenty to forty seconds, watching extraction of 

 fuchsin stain under microscope. Differentiate the blue stain in 

 96 per cent, alcohol, then absolute, xylol, and balsam. The 

 chromatin is generally blue, mitochondria (and occasionally Golgi 

 apparatus) are red, and the ground cytoplasm is golden-yellowish 

 to green. This modification of Altmann's method is a most 

 brilliant three-colour stain which is highly recommended. We 

 have found that it is useful for histological as well as cytological 

 purposes ; sections of Annelids, or of flat-worms, for instance, 

 prepared by Champy-Kull show beautiful colour gradations in 

 their different tissues. The preparations begin to fade after a 

 year. 



After Champy-Kull fixation you can : (o) stain in iron haema- 



