216 PROCEEDINGS OF THE ACADEMY OF [1896. 



In spite of these discouraging facts this field of research seems to 

 me well worth especial labor and care and the only feasible method 

 is to continue the careful investigations of Arnaud, Courchet, Im- 

 mendorffand Zimmermann which will no doubt shed further light 

 on this hitherto dark field, of interest alike to the botanist, chemist 

 and physiologist. 



I selected the aril of the seed of Celastrus scandens, since some of 

 the peculiarities of the pigment are well marked and I desired to 

 find if possible its place in Zimmermann's four pigments. 



Carotin is found as a crystalline secretion in the root of Daucus 

 Carota also in red flowers and fruits of other plants. It imparts a 

 blood red color to carbon bisulphide in which it is readily soluble 

 and from which it may be obtained in the form of a crystalline pre- 

 cipitate by the addition of alcohol. I found that the pigment of the 

 aril of Celastrus scandens was soluble in carbon bisulphide forming 

 a deep red solution, but no precipitate was visible in the addition of 

 alcohol. After evaporation an amorphous sticky mass resulted and 

 it will thus be seen that it differs from carotin in this respect. 



In using various well known solvents I found their effects as 

 follows : 



1. Water, no visible effect. 



2. Alcohol, 50 per cent no visible effect on chromatophores, but 

 the solution was slightly tinged yellow. 



3. Alcohol absolute, more soluble; the solution of a deeper 

 tinge. 



4. Ether, about like 50 per cent alcohol in color but a greater 

 amount of yellow residue left on evaporation.^ 



5. Aceton, about like 50 per cent alcohol, 



6. Chloroform, much more soluble, solution deep red. 



7. Carbon bisulphide, similar to chloroform, solution deep red. 

 Carotin " according to Arnaud is insoluble in water, almost so in 



alcohol, very slightly soluble in ether, and most so in chloroform 

 and carbon bisulphide. These solutions are colored yellow to orange 

 yellow, according to their degree of concentration, while the solution 

 of carotin in carbon bisulphide is always blood red." * 



' It is possible that the yellow matter with which the cuticle is impregnated 

 influences to some extent the color imparted to the solvents. This requires 

 further attention. 



* Zimmermann, Microtechnique, p. 102. 



