110 Transactions of the Society. 



Tip off and add a saturated solution of picric acid in water, pre- 

 viously diluted by one-half. Heat and leave as before. Blot, 

 dip into either 00 p.c. or absolute alcohol, and observe differentia- 

 tion under microscope. Pass to xylol quickly and mount in 

 balsam. Golgi elements black, mitochondria red to purplish, 

 ground cytoplasm yellowish. Eest like Kopsch. 



IV. Champj and Flcmming {F. W. A.). — Fix small pieces of 

 tissue (circa 3-5 mm. in diameter) from one day to a week in 

 either Cliampy or Flemming without acetic acid, strong formula. 

 I then find that nine to ten hours in iron-alum, and twelve to 

 tAventy hours in hiematoxylin, gives the most beautiful results. 

 Longer immersion in the watery mordant or stain produces a 

 macerated effect, which however is slight. . Champy is excellent 

 for vertebrate tissues, and especially for amphibia. (The acetic 

 acid as added to the iiuids of Benda and Meves produces distortion 

 of delicate cell organs.) Mitochondria black ; Golgi apparatus, 

 when evident, black. 



V. Mann's Corrosive Osniic. — Fix tissue from one day to a 

 week in the following solution: — Osmic acid of 1 p.c, 50 parts ; 

 corrosive sublimate, saturated solution in normal saline, 50 parts. 

 I then find that iron-htematoxylin is the most suitable stain. 

 Ground cytoplasm rarely quite perfect. This method is sometimes 

 successful in demonstrating the Golgi apparatus where other 

 techniques fail. Golgi elements and mitochondria black. 



Notes re Kopsch Method. — («) Never use cork, as it absorbs the 

 osmic vapour and completely disintegrates the solution, {h) The 

 black fluid left, after the lapse of a week or two, may be 

 collected in a bottle ; such fluid contains a good deal of osmic acid, 

 and the black matter can be precipitated by adding one or two 

 drops of chromic acid of 1 p.c. The precipitate can be filtered off 

 after a day and the recovered fluid used for laboratory work on 

 fat, etc. 



VI. Finally, in attempting to demonstrate the Golgi apparatus 

 in a cell, if other methods have failed, Cajal's or Golgi s methods 

 may succeed. I give below the method of Cajal, which I find 

 excellent. (For Golgi, see 10.) 



1. Fix small pieces of tissue or organ for from nine to eleven 

 hours : — Uranium nitrate, 1 grm. ; formol, 15 c.cm. (commercial will 

 do) ; distilled water, 100 c.cm. 



2. Eemove tissue and wash in three changes of distilled water 

 for ten minutes. 



3. Transfer to silver-nitrate bath of 1 • 5 p.c. for about thirty- 

 five hours. Wash as in paragraph 2. 



4. Transfer tissues to the following reducing fluid: — Hydro- 

 quinone, 2 grm. ; formol, 6 c.cm. ; distilled water, 100 c.cm. Add 

 anhydrous sodium sulphite, about 0*15-0 '25 grm., till the solution 

 has a yellow colour. This solution may go bad after a time. The 



