1S93.] 



MICKOSCOI^ICAL JOURNAL. 



53 



The advantage to be gained by employing a glass guiding I'od 

 in pouring liquids from vessels having straight sides and rim with- 



out lip is illustrated in Fig. i (A and B). Greasing the rim and 

 outside surface just below the rim will also prevent the liquid from 

 clinging to the glass vessel and cause it to flow in a full, round 

 stream. — Bullet iji of PJiannacy. 



Dr. V. A. Moore's Holder for Cover-Glasses. — When 

 sections of animal tissue are fastened to cover-glasses* in order to 

 transfer them from one bath to another during the process of their 

 preparation for mounting, there seems to be no reservoir in the 

 list of histological apparatus that is well suited to their use. The 

 ordinarv solid watch-glass, crystallizing dish, etc., are objection- 

 able, as the cover-glass falls at once to the bottom, from which it 

 is removed with difficulty, and, again, when several specimens 

 are being prepared at the same time they almost invariably run 

 together in the form of rojilemix^ the separation of which is at- 

 tended with great danger to the sections. These difficulties have 

 rendered this otherwise very convenient method of handling sec- 

 tions, when from their nature a support is necessary, so objection- 

 able that the cover-glass is seldom used by histologists for this 

 purpose. The following apparatus is for holding the cover-glass 

 during the hydration, staining, dehydration, etc., of the sections, 

 and has been found to work admirably : 



The apparatus consists simply of a '' double dish " 15 centime- 

 ters in diameter and 3.^ centimeters in depth, in which glass rods 

 are arranged parallel to each other and separated by a distance of 

 about 4 millimeters. The rods are about 5 millimeters in diam- 

 eter. They are raised about 3 millimeters from the bottom of 

 the dish and fastened only at the extremities, thus permitting of a 

 free circulation of the liquids. The cover-glasses are placed on 

 edge between the rods, against which they rest (Fig. i). A res- 



* In fastening sections to cover-glasses care must be exercised in the choice of some method 

 of fixation which will not leave a film on the cover that will be tinted to any degree by the stain 

 used. The gelatin, albumen, and collodion processes are not always satisfactory when certain 

 aniline dyes are subsequently empl6yed. A method which seems admirably adapted to this 

 process of handling sections is the paraffin-alcohol method described by Dr. A. Canini in the 

 Archrv. /. A'lat. u Fhys . , Phys. Ablli.. iS8j, p. 147. It cunsisis simply in placing the section 

 on a cover-glass directly from the seel ion-knife and adding a few drops of dilute alcohol (60 to 

 70 per cent.). The cover is then placed in a paraffin oven at a temperature of about 50° C, 

 where it remains until the alcohol is evaporated. This method was also highly recommended 

 by Ogata in his work on the pancreas cell. It is applicable only to sections cut by the paraffin 

 piethod. 



