436 RESEARCHES ON FUNGI 



upon which it was based. In the case of the Wild Mushroom, on 

 the other hand, no synthetic drawings will be given, and we shall 

 confine our attention to a set of special sections from which a 

 synthetic illustration might be constructed, were such required. 

 Our plan will be to study a series of such sections which show the 

 hymenium in : (1) an early stage of its activity, (2) an almost 

 exhausted stage, and (3) a completely exhausted stage. These 

 sections were all cut with a hand-razor from living gills and 

 mounted in water, after which the cells were drawn with the 

 camera lucida. The illustrations representing these sections on 

 subsequent pages of this Chapter are the first of their kind to be 

 published, and I shall not hesitate, therefore, to tell the secret of 

 my success in making them. I used perfectly fresh mushrooms, cut 

 sections through the thickest part of a gill with a sharp razor held 

 in the hand, examined the sections in the living state immedi- 

 ately after they had been mounted in water, and interpreted the 

 sections in the light of the knowledge and experience which I had 

 gained during my study of Panaeolus campanulatus and Stropharia 

 semiglobata. The microscope employed was a Zeiss, eyepiece 

 no. 4 and objective FF. The original camera-lucida sketches were 

 made with a magnification of 1,040 diameters and then photo- 

 graphed with a lantern-slide-making apparatus. The negatives so 

 obtained were then put into a lantern and projected on a sheet 

 of white paper, so that the magnification- of the original drawings 

 was increased from 1,040 diameters to 1,560. The projections were 

 then traced out on the paper with a pencil. The tracings so 

 obtained were then made into black-and-white drawings with 

 ink, and these drawings, after reduction to two-thirds by the 

 block- maker, are reproduced as Figs. 148-152. 



The illustrations of the special sections, about to be described, 

 not only show the general succession of basidia but exhibit for the 

 first time, so far as the Mushroom is concerned : (1) collapsed 

 past-generations basidia which hitherto have been overlooked, 

 (2) paraphyses which never produce spores and are destined from 

 the first to remain sterile, and (3) the true relations of the hymenial 

 elements with the subhymenium. 



Camera-lucida Studies of the Young Hymenium. In Fig. 148 



