258 TRANSACTIONS OF THE CANADIAN INSTITUTE. [VoL. 1. 



changes in the pancreatic cells and I believe that it was attained in 

 every case. The piece of tissue was after removal from either of these 

 fluids, washed for a few seconds in distilled water, then transferred to "joy 

 alcohol for three hours, in the case of the corrosive sublimate prepara- 

 tion, and for twenty-four hours, when the Flemming's Fluid was used. 

 When the latter was allowed to act longer than one hour, the alcohol 

 was changed as often as it presented a trace of chromic acid coloration. 

 The hardening was completed by a stay of twenty-four hours in 95 per 

 cent alcohol. The organ was now transferred to the staining fluid, alum 

 hematoxylin, (a few drops of a saturated solution of haematoxylin in ab- 

 solute alcohol to a saturated solution of pure ammonia alum in distilled 

 water: allowed to stand one month in summer sunlight before using, and 

 kept from deterioration by crystals of thymol), for ten to fifteen hours. In 

 order to prevent overstaining, I found it advisable to dilute the original 

 haematoxylin solution with twice its volume of distilled water, in which 

 dilution, after the time allowed, there is only a pure chromatin stain in 

 the nuclei of the pancreatic cells and a faint shade of purplish blue in 

 the nebenkerne. The objects are now washed in distilled water to 

 remove the alum and the excess of the staining fluid, and are then put 

 in a quantity of a i per cent solution of eosin in 30 per cent alcohol for 

 from two to three hours. Washed in 95 per cent alcohol, till the latter 

 was but faintly colored with the eosin after one hour's action, the 

 object was placed in absolute alcohol for five minutes, then in pure 

 chloroform for fifteen hours on the average, after which it was kept 

 in a saturated solution of paraffin in chloroform at 35°C. for about 

 eight hours, and finally placed for a like period in melted paraffin 

 (melting point 52°C). The sections were made of a thickness not ex- 

 ceeding ^li. with the Thoma-Yung microtome and fixed by the ribbon 

 method in series to the slide with a diluted Schallibaum's clove oil- 

 collodion mixture, (clove oil i volume, collodion 3, equal parts of 

 absolute alcohol and ether 3). -^ I used, sometimes in the case of the 

 corrosive sublimate preparations, the Gaule method of fastening the 

 paraffin sections to slide, but, as the process of staining on the slide was 

 not employed, except when the action of safifranin was required, it did 

 not present any points of advantage over the other, which was the 

 quicker. The paraffin was removed with benzole and the sections 

 mounted in benzole balsam. 



The staining of the object as a whole with haematoxylin and eosin has 

 the advantages of giving a regular and uniform depth of reaction in the 

 various sections and the different parts of each, and of preventing the 

 loss of important elements entailed by the process of staining on the 

 slide. I found that a little practice enabled one to judge of the length 



