306 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



of esrirs that its entire absence is exceptional. In a free solid 

 form, as in the shell, it is generally of a peculiar brownish 

 red. 



Second, Oocyan. This when dissolved in alcohol is of a 

 fine blue color. It is readily soluble in neutral alcohol, and 

 thus can be separated from oorhodeine. It is, however, often 

 associated with yellow substances that can not be easily re- 

 moved. 



Third, Banded oocyan. This is also of a fine blue color, 

 but differing very decidedly in its spectrum from oocyan. 



Fourth, Yellow ooxanthine. This may best be obtained 

 from moderately fresh emu-eggs. 



Fifth, Rufous ooxanthine. This, so far, has only been 

 found in the different species of Tinamon. 



Sixth, Substance giving narroio absorption bands in the 

 red. This Mr. Sorby has not been able to separate in suffi- 

 cient quantity to determine whether its real color is blue, 

 green, or brown. 



Seventh, Lichnoxanthine. This occurs in greater or less 

 amount in almost all classes of plants, and is most especially 

 abundant in the lichens and fungi. Mr. Sorby thinks this 

 may possibly have been derived, to a certain degree, from 

 the decayed vegetable matter of the nest, or, in cases of 

 eggs which have been kept long, may be partly due to the 

 growth of minute fungi ; but, at the same time, a very closely 

 allied, if not identical substance, does really appear to be a 

 normal constituent of the shell of eggs having a peculiar 

 brick-red color. 



In reference to the colors of eggs, Mr. Sorby remarks that 

 the varying tints are due to the presence of either of these 

 primary coloring matters, and this in a separate condition, or 

 mixed to a ijreater or less desjree with others. Thus the 

 various shades of green, passing from blue-green to a fine 

 malachite-green and to a yellow-green, are due to a variable 

 mixture of oocyan wdth yellow ooxanthine. It is well known 

 that many green eggs turn blue on long keeping. This is 

 explained by the fact that yellow ooxanthine is much more 

 easily destroyed by oxidation resulting from exposure to 

 light than oocyan, the oocyan or the blue color remaining 

 unchanged. 



Mr. Sorby thinks that it will be very difficult to make use 



