Laws of Fluctuations 725 



If the deviations become greater, they might 

 even become detrimental. The flowers of the 

 St. Johnswort, or Hypericum perforatum, 

 usually have five petals, but the number varies 

 from three to eight or more. Bees could hardly 

 be misled by such deviations. The carpels of 

 buttercups and columbines, the cells in the cap- 

 sules of cotton and many other plants are vari- 

 able in number. The number of seeds is there- 

 by regulated in accordance with the available 

 nourishment, but whether any other useful pur- 

 pose is served, remains an open question. Vari- 

 ations in the honey-guides or in the pattern of 

 color-designs might easily become injurious by 

 deceiving insects, and such instances as the 

 great variability of the spots on the corolla of 

 some cultivated species of monkey-flowers, for 

 instance, the Mimulus quinquevulnerus, could 

 hardly be expected to occur in wild plants. For 

 here the dark brown spots vary between nearly 

 complete deficiency up to such predominancy as 

 almost to hide the pale yellow ground-color. 



After this hasty survey of the causes of fluc- 

 tuating variability, we now come to a discussion 

 of Quetelet's law. It asserts that the deviations 

 from the average obey the law of probability. 

 They behave as if they were dependent on 

 chance only. 



Everyone knows that the law of Quetelet can 



