523 
yellow or orange oily globules and masses, which have been for- 
med in the cells and which contain the carotinoid, also lose more 
or less of their colour. Sulphuric acid then no longer colours them 
blue or much more feebly than at the beginning of the experiment. 
The carotinoid decomposes without erystallising out. This decompo- 
sition is easily confirmed in Chelidonium majus, Narcissus Pseudo- 
narcissus, Doronicum Pardalianches and Tulipa hortensis, for instance. 
Resorcinol Method. 
Tswert ’) has described a method of erystallising the carotinoids from 
plants and parts of plants under the microscope. The objects are 
placed on the microscope slide in a concentrated solution of resorci- 
nol, containing 10 to 12 parts of resorcinol in 10 parts of water. 
I have used this method in eight cases, namely, in the leaves of 
Urtica dioica, in the flowers of Chelidonium majus, Erysimum Perof- 
skianum, Gazania splendens, Calceolaria rugosa and Narcissus Pseu- 
donarcissus, in Cladophora sp. and in Haematococeus pluvialis. In 
five cases, namely, in Urtica, Chelidonium, Calceolaria, Narcissus 
and Cladophora erystals separated rather quickly. In Chelidonium, 
Calceolaria and Cladophora erystals appeared in the cells, in the 
other two cases in and around the preparations. Erysimum, Gazania 
and Haematoeoecus which had given positive results with the potash 
method, gave negative results with the resorcinol solution. In the 
case of Haematococcus pluvialis JacoBskN’) was also unable to obtain 
separation of crystals. 
The shape of the erystals differs greatly. When with Motiscn’s 
reagent red and orange-yellow crystals were obtained, crystals of the 
same colour were formed with Tswert’s reagent in those cases in 
which the experiment gave a positive result. With respect to reagents 
the crystals behave in the same way as the carotinoid crystals obtained 
by the potash method. 
Tswerr *) has also pointed out the variation in the crystals and 
has shown in Lamium by his adsorption method that different che- 
mical bodies are present, carotin and xanthophyll. It seems to me 
that Tswerr’s method will be applicable with success to many cases. 
1) M. Tswerr, Uber den makro- und mikrochemischen Nachweis des Carotins, 
Ber. d. d. bot. Ges. 29. Jahrg. Heft 9, 1911, p. 630. 
2) H. CG. Jacossen, Die Kulturbedingungen von Haematococcus pluvialis, Folia Micro- 
biologica J, 1912, p. 25. 
ke. 
