SUNSHINE AND LIFE 81 



assumed an upright position. Darkness was nearly 

 always chosen for the liberation of the spores, but 

 in a few instances a small number were released 

 during the daytime, and it was noticed that when 

 this did occur they were invariably discharged on 

 the side away from the source of light. In various 

 other ways he confirmed this interesting observa- 

 tion, and found that the fruit of the mould was 

 invariably discharged in the opposite direction to 

 that in which the stalk had previously inclined 

 under the influence of light. The force with 

 which the spores were discharged varied very 

 considerably, sometimes being cast to a distance 

 of four inches or more from the stalk, and some- 

 times being found close to and even on the stalk. 



The manner in which sunshine may also modify 

 the pigment-producing powers of micro-organisms 

 is remarkable. 



Many microbes are able to elaborate when grown 

 on various culture media, such as gelatine or slices 

 of potato, most brilliant and beautiful pigments 

 ranging from intense blood-red to the most deli- 

 cate shades of pink, and embracing every grada- 

 tion of yellow, as well as browns, greens, and 

 violets. Now it has been found that some of these 

 pigment-producing bacteria, when exposed to sun- 

 shine on these nutritive materials, fail to exhibit 

 their characteristic colour, although the duration 

 G 



