XX1II,2. Ilulicr: Metlidd of i)reparing large Niiml)ers of Sections. 189 



tliis is (iisi)laL'('(l uitli alcoliol. Tlie scctions are then covcrcd witli a tliin 

 Solution of ccUoidin, its solvent allowed to cvai)oratc and tlic plate placcd 

 into watcr in wliicii thc slieet of cdloidin witli tlio ailiicrcnt sections 

 hocomes loosoned. By means of this OüRKtiiA-GuLLAXD nietliod, a desired 

 nuraber of paraffin sections are convcrted into celloidin sections, tlie cel- 

 loidin (or photoxylin) bcing in the form of a single sheet whicli niay readily 

 be raanipulated in tlie various steps of staining, deliydration and Clearing. 

 Strasser (4) has modified the original Weigert (1) metliod in anotiier 

 direction, suggesting the use of paper strips coated witli guni Arabic 

 foUowed hy a coating witli collodium, and to make such strips adhesive 

 for paraffin sections a further coating with collodium (2 jiarts) and clove 

 oil (1 part). The parafHn sections, wliich need to be free froin folds (and 

 to obtain such Strasser suggests the use of a scction-stretcher) are ar- 

 rangcd on these prepared strips of paper and are then covered with a 

 layer of tlie collodium -clove oil Solution. Strasser (5 — H) has further 

 moditied and as he states, simplified liis method, and calls special attention 

 to the ease with whicli paraffin sections thus fixed to strips raay be stored 

 for a long time ready for future use. For the details of Strasser's method, 

 his especially constructed microtome and section-stretcher, the reader is 

 referred to the original pulilications. A further method, based on a differcnt 

 principle than the methods above enumerated, for staining large numbers 

 of paraffin sections , with the possibility of obtaining Single sections has 

 quite recently been recommended by Heidenhain (7). The method of 

 procedure suggested is essentially the same as that iised for fixing sec- 

 tions to slides with the water-albuiuen method, except that thin mica-plates 

 (Glimmerplatten) of the required size are used. The mica-plates are 

 to be thoroughly cleaned , but without causing breaks or cracks. The 

 plates are then covered with a layer of water and albumen fixative or a 

 Solution of serum albumen. The ribbons of paraffin sections are arranged 

 on such plates and placed on a warming table modified from that described 

 by BoRX in Order to Hatten out the sections. As soon as this is accom- 

 plished the excess of water is allowed to drain off and the mica-plate with 

 the adherent sections placed in a warm oven with a tcmperature of 33" 

 to 35°. After the evaporation of the water the paraffin is removed in the 

 usual way and the sections are stained as desired. The mica-plates are 

 cut up as desired after staining and Clearing the sections. This method 

 has not as yet been tried in this laboratory, but would on a priori 

 grounds seem open to certain objections, as perfectly clear mica-plates of 

 any size are not readily obtained and only such would , it would seem, 

 meet the requirements. All the othcr methods mentioned posscss certain 

 disadvantages as luay be attested by the fact that they have not met 

 with general acceptance. With the Obregia-Gulland method, the paraffin 

 sections if at all folded are oftcn difficult to fiatten out and thc Strasser 

 method is not easy of manipulation and recjuires special apparatus for its 

 most successful Operation. For this reason, we have been in this labo- 

 ratory for some time engaged in modifying more particularly the Obregia- 

 Gulland method with an endeavor to make it more generally satisfactory 

 and casv of m.-inipulation so as to rid it of certain of its objcctionable 



