CURREY, ON FUNGI. 119 



The spores must be placed on a common glass slide in a drop 

 of alcohol, so as to drive away the air, which otherwise clings 

 pertinaciously to the mass of spores. Before the alcohol has 

 quite evaporated, two or three drops of strong nitric acid 

 must be added, a piece of thin glass must be placed over the 

 spores, and the slide should then be gradually warmed over 

 a spirit lamp. The acid must not be allowed to boil, at least 

 not for any length of time, because the action then becomes 

 so powerful as to obliterate the structures which it is wished 

 to exhibit. By following this process it will be seen that 

 the fruit consists of an outer colourless membrane, almost 

 transparent, which in most of the species is studded over 

 with small tubercles, being prominences of the membrane 

 itself. This membrane encloses a number of cells, being the 

 cells constituting the apparent joints of the fruit, and which 

 in their natural state are of a squarish or oblong shape, occa- 

 sioned by their mutual pressure. Fig. 15 (PI. VIII) represents 

 a spore which has been acted on by the acid, but not to a 

 sufficient extent to dissolve or rupture the outer membrane ; 

 which, however, has swollen and become loosened from the 

 inner cells. When by the action of the acid the outer hyaline 

 membrane is ruptured or dissolved, these cells escape, become 

 detached from one another, and assume the shape shown in 

 figs. 7 and 8. 



They exhibit a broad brownish or yellow ring surrounding 

 a central area of paler colour, and in the interior of each of 

 these areas is to be seen, what for distinction may be called 

 an inner cell, which in its normal form is globular, but which 

 frequently assumes an irregular shape. Fig. 8 represents a 

 ringed cell with its inner cell filling the whole of the cavity, 

 and fig. 7 shows a ringed cell with an inner cell of irregular 

 shape. 1 have not yet been able quite to satisfy myself as 

 to the stmctm-e of the ringed cells. It appears at first sight 

 as if the ring were an integral part of the cell itself, so that 

 if the observer be supposed to be looking upon the pole of 

 the cell, the ring woidd form a mass of Ijulging matter at its 

 equator ; but opposed to this is the fact that under the action 

 of the nitric acid the ring sometimes entirely disappears, 

 leaving a pellucid, globular, colourless cell, having the inner 

 cell in its interior as shown in figs. 9 and 10. The ring is 

 sometimes marked with concentric lines having the appearance 

 of wrinkles in the membrane. 



Fig. 11 represents an inner cell quite free, exhibiting its 

 granular contents and a central nucleus. The inner cells have 

 far greater power of resisting the action of the acid than the 

 sporangial membrane or the ringed cells, for if the acid be over- 



VOL. V. M 



