144 Royal Society : — 



4. That each cell should receive no light hut that transmitted hy 

 its proper cover. 



One of these six cells was open to the air and to light ; one was 

 covered with ordinary white glass ; one was made completely dark 

 by a covering of blackened opaque glass ; one was covered with blue, 

 one with greenish yellow, and one with red glass. The transmit- 

 ting and absorbing powers of these glasses were detfiiled from expe- 

 riments made upon them by Mr. Cornelius Hanbury, jun., and by 

 the author. 



The apparatus used for the Silkworms was, in all essential par- 

 ticulars, the same as that for the Tadpoles, only without water. 



A tabulated analysis of the daily journal kept during the experi- 

 ments was given, and its separate items compared and discussed ; 

 after which the author concluded his Paper with the following resume. 



If we may venture to reason on so small a numlier of observa- 

 tions, so far as the results of these experiments are concerned, the 

 following propositions may be advanced. 



AH other conditions being the same, (1.) The Ova of Insects 

 ftre not directly influenced in their development by white light, by 

 the different coloured rays, or by darkness. 



(2.) The Larvae of Insects are not directly influenced in their 

 development, growth, nutrition, or metamorphoses by white light, 

 by the different coloured rays, or by darkness. 



(3.) The Larvae of Batrachian Reptiles are not directly influenced 

 in their development, growth, nutrition, or metamorphoses bj^ white 

 light, by the different coloured rays, or by darkness. 



(4.) The Materials necessary to the Colour of Insects and Rep- 

 tiles ai"e prepared equally under the influence of Avhite light, of the 

 different coloured rays, and of darkness. 



These results are so opposed to preconceived ideas upon the sub- 

 ject to which they relate, that they cannot fail to excite some surprise 

 and incredulity ; when, however, they are carefully considered, they 

 assume a theoretical probability, which assists us in believing that 

 the practical results are without fallacy. 



(«.) With regard to the development of the ovum, when we con- 

 sider the unity of plan which appears to preside over the germs of 

 the simplest and of the most complicated forms, and the infinite 

 variety of external conditions in which these germs are jdaced 

 throughout the animal kingdom, we are led to the conclusion that 

 their development must be so arranged as to be independent of the 

 direct influence of light, 



(6.) That after emerying from the ovum the animal is not di- 

 rectly influenced by light, is more diflScult, at first, to believe, be- 

 cause experience seems to have taught us that " to live without 

 light is to live without health ;" but this familiar fact may be at 

 once disposed of in the argument and explained by its coincident, 

 tbat, under ordinary circumstances, the admission of light is in- 

 separably connected with, 



1 . The regulation of external temperature. 



2. The free circulation of a respiratory medium. 



