ZOOLOGY AND BOTANY, MICBOSCOPY, ETC. 917 



tion of tte prevalence of certain colours in spring flowers, as contrasted 

 with those of autumn and summer. 



The common spring flowers of England were reckoned as 64, 

 and these were included, as regards colour, under five heads, viz. 

 (1) white, (2) green, (3) yellow, (4) red and pink, (.5) blue and violet. 

 The proportion was found to be as follows: — white, 26, or 40*5 per 

 cent. ; green, 9, or 14* 1 per cent. ; yellow, 13, or 20*3 per cent. ; red 

 and pink, 5, or 7*8 per cent.; blue and violet, 11, or 17-4 per cent. 

 The chief feature in this table is the great preponderance of white, as 

 compared -ndth other times of the year ; yellow is also greatly in excess, 

 while the number of red and pink flowers is extremely small. Taking, 

 now, 50 early spring Swiss flowers, the following list is obtained : — 

 White, 18, or 36 per cent. ; green, 1, or 2 per cent. ; red and pink, 10, 

 or 20 per cent. : blue and violet, 8, or 16 per cent. The chief points of 

 contrast in this list, as compared with the first, are the smaller pro- 

 portion of white and green, and the very much larger proportion of 

 red and pink. White and green differ from all the other shades, as 

 indicating rather the absence than the presence of colour. Seeing, 

 therefore, that the bright- coloured fluid pigments of petals are formed 

 only under the influence of a sufiicient supply of light and heat, the 

 large proportion of green and white in our early spring flowers is 

 easily accounted for. Then, with regard to yellow, M. Flahaut 

 observes that "a solid insoluble pigment, the xanthine of Fremy and 

 Cloez, is in the first place to be distinguished from all the soluble 

 colouring matters, all of which are acted on very readily by reagents, 

 and which are usually formed only in the epidermal cells." This 

 xanthine Fremy states to occur always in the " form of clearly defined 

 grains, occasionally in the epidermal, much more often in the deeper- 

 lying cells, slowly soluble in alcohol and potassa. It is in all proba- 

 bility a modification of chlorophyll." The plants in which he found 

 this substance are all early-flowering spring plants. The colours 

 which pre-eminently distinguish our summer and autumn flora, the 

 reds, pinks, blues, and some yellows (not due to xanthine, but to a 

 soluble yellow pigment), are caused by the presence of substances 

 which require both a strong light and a high temperature for their 

 production ; and Batalin has shown this to be especially the case with 

 the red colouring substance. 



The difference between the prevailing colours of the spring flowers 

 in England and in Switzerland is due to the same cause. Owing 

 partly to the spring being a month later, partly to the more southern 

 latitude and consequent greater elevation of the sun, partly to the 

 clearer air of a high altitude, the light which opens the earliest 

 spring flowers is much stronger in Switzerland than in England. 



Action of Anaesthetics on the Sensitive Organs of Plants.*— 

 In order to determine the question whether the effect of chloroform 

 and ether in suspending the irritability of sensitive organs is due to 

 the cold produced by their application, C Cugini used them in an 

 atmosphere of the steam of boiling water. In the cases both of the 



* Nuov. Giorn. Bot. Ital., xiii. (1881) pp. 288-91. 



