502 EDWARD A. BURT ON A 



2. The receptaculum is formed by the joint action of both the cortical and 

 medullary tissues. Of these the cortical constituent develops into the pseudoparenchyma 

 of the walls, while the enclosed medullary bundles of the chambers finally become 

 gelatinous and disappear, their most manifest function being apparently that of 

 preventing the elongation of the chambers until the completed formation of the folded 

 walls of pseudoparenchyma has provided a mechanism for quickly raising the gleba 

 aloft at maturity under suitable conditions. 



3. The straightening out of the folds in the elongation of the stipe seems to be 

 due to turgescence of the cells at the ends of the folds, as first shown by Fischer, and 

 not due to inflation of the chambers by a gas. 



Methods Used. 



The material was stained in bulk with Mayer's paracarmine. 1 This penetrated well 

 and gave quite satisfactory results. It was necessary to use an alcoholic stain on 

 account of the gelatinization of the medullary tissues when left in bulk in an aqueous 

 stain for more than a few minutes. After dehydration the material was cleared in oil 

 of cedar-wood or in chloroform and imbedded in paraffin. The sections were mounted 

 on the slide with Mayer's albumen medium. After removal of their paraffin with xylol, 

 they were run down through the grades of alcohol to water and then stained on the 

 slide from 1 to 5 minutes in a dilute aqueous solution of safranin. After washing 

 with water, the series were then mounted in a dilute glycerine consisting of two 

 volumes of concentrated glycerine and one volume of distilled water. An excess of this 

 mounting medium was used, and it was allowed to concentrate for several days by 

 evaporation from under the edge of the cover-glass. Sealing such large mounts is often 

 troublesome. After cleaning they were closed with hot glycerine jelly and then 

 finished with Bell's cement, after the method recommended by Lee. 2 



The attempt was made to stain the sections on the slide when brought to the proper 

 grade of alcohol with the mixture of alcoholic safranin and anilin water, after the formula 

 of Zwaardemaker, 3 but the differential stain obtained was not so satisfactory as with the 

 aqueous safranin. 



The use of Canada balsam, in order to save some of the labor of mounting long series 

 in glycerine, had to be given up as the true relations to one another of hyphae lying in 

 different planes were less satisfactorily shown in that medium than in glycerine. 



1 P. Mayer in Mitth. zool. stat. zuNeapel, X, 3, 1892, 

 p. 491 ; also in Lee : Microtomist's vade-mecum, 3d ed., p. 

 106. 



2 Lee: Microtomist's vade-mecum, 3d ed., p. 252 and 



254. 



3 See Lee: Microtomist's vade-mecum, 3d ed., p. 65. 



