THE VIOLENT PROJECTION OF SPORES 



139 



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B 



the direction in which the cyhnder is viewed with the microscope. 

 Let A B C D be a section of the cylinder placed within the range 

 of focus. Then to the observer the section will have the appearance 

 of a truncated cone, ahcd. The truly vertical sides of the section 

 of the cylinder will appear inclined as shown in the figure.^ Now 

 let the arrows X and Y indicate the 

 truly vertical paths of two spores falling 

 parallel to the sides AB and CD of the 

 cylinder. Then, when observed with the 

 microscope, the course of the spores will 

 appear to be as indicated by the arrow^s 

 X and y, i.e. the illusion will be created 

 that the spores are moving more or less 

 horizontally outAvards from the cylinder. 

 The apparent bombardment of the 

 spores into the spaces between the gills, 

 which one sees on looking vertically 

 downwards upon a section like that in 

 Fig. 48, may now be explained. Let 

 AA in Fig. 50 represent a vertical section 

 taken transversely through three of the 

 gills, and let the arrows placed parallel 

 to, and at a little distance from, their 

 vertical sides, represent the true paths 

 of six spores falling vertically. Then, as 

 shown at BB, when the low power ob- 

 jective of the microscope is placed in the 

 position of the arrow 0, one apparently 

 observes spores being shot outwards from 

 both sides of the gill immediately below, 

 and, when one observes in the direction 

 indicated by either of the arrows P or Q, one apparently sees the spores 

 being shot outwards from two gills into the interlamellar spaces. 



^ The explanation of the phenomenon seems to be due to the fact that the 

 area of the objective is lari^e compared with diameter of the cylinder, so that 

 different parts of the objecti\e, as it were, can see different parts of the cylinder. 

 With the low power of the microscope one can see simultaneously both sides of 

 an ordinary glass slide placed vertically. 



Fig. £0. — Above at AA is shown 

 a ti'ansverse and vertical section 

 through three gills of a piece 

 of a pileus like that in Fig. 48. 

 When observed from above in 

 the directions of the arrows O, 

 P, and Q, the range of focus 

 is supposed to be between the 

 dotted lines. The four arrows 

 between the gill-sections indi- 

 cate the laaths of four spores 

 falling parallel toandabout one- 

 tenth of a millimetre from the 

 hymenial surfaces. Below at 

 BB is shown the apparent shape 

 of the parts of the gills in focus 

 and the apparent paths of the 

 spores. The latter, although 

 falling vertically, appear to be 

 shot outwards from the hy- 

 menial surfaces into the spaces 

 between the gills. 



