35 
not altered? In attempting to answer this question he was led to 
test the conduct of a large number of substances toward guaiacum, 
among them a large number of roots, fresh and dried, several gums, 
milk, soap, etc. Among the fresli roots tested the following were 
found by this observer to blue guaiacum: Comfrey C Symphytum 
consolida, L.), dandelion ( Leontodon taraxacum), common iris (Iris 
germanica) , chicory ( Cichorium intybus) , thistle ( Eryngium campestre), 
white water lily ( Nymphyaea alba), potato (Solarium tuberosum), 
bryony (Bryonia dioica ), elecampane (Inula Jielenium), marshmallow 
(Althea officinalis), carrot (Caucus carota), licorice (Glycyrrhiza 
glabra), turnip (Napis sativa), burdock (Arctium lappa), colchicum 
(Colchicum autumnale), soapwort (Saponaria officinalis), scurvy 
grass (Cochlearia officinalis), fumitory (Fumaria officinalis), figwort 
(Scrophularia officinalis), sorrel (Rumex acetosa), viper’s grass 
(Scorzonera hispanica), asparagus (Asparagus officinalis), borage 
(Borago officinalis), angelica (Angelica archangelica) , onion (Allium 
caepa), wild radish (Cochlearia armoracia, L.), little radish (Raphanus 
sativus). The fresh root of the chicory, especially in the fall of the 
year, was found to give with guaiacum a magnificent blue color. So 
also the fresh root of the water lily produced a very intense colora- 
tion at first, which faded rapidly on standing. For the most part 
the dried roots gave no color with guaiacum. Neither did the fresh 
roots of the following plants: Patience (Rumex acutus, L.), male 
fern (Poly podium filix mas), strawberry (Frag aria vesca) . Further- 
more he found that light was without influence on the development 
of the blue color of guaiacum by roots capable of effecting this change. 
Thus the parsnip caused the bluing of guaiacum in the dark. Simi- 
larly when guaiacum and white soap were mixed together there 
resulted a. greenish mass which finally took on the color of verdigris, 
and the interior of the mass acquired a deep blue color. Obviously 
the light could not have been responsible for this increase of the color 
in the interior portions of the mixture. He also observed that milk 
has the power of bluing guaiacum, and that this change of color takes 
place in a vacuum. He concludes, therefore, that in the bluing of 
guaiacum by milk, air is not responsible for the change of color. On 
boiling, however, milk lost its power to blue guaiacum, and in general, 
those substances, gums and plant roots, which have the power of 
bluing guaiacum, lose this power by heat. Thus the potato, parsnip, 
and beechnut (Fagus castanea), cooked in closed vessels in their own 
juices, do not react with either the powdered resin or the tincture. 
He therefore concluded that the substance or substances causing the 
bluing of guaiacum are volatile and possibly condensable. He was 
therefore led to test the conduct of the distillate obtained from milk 
toward guaiacum, with the result, however, that no change of 
color was produced. He therefore had to renounce the idea that the 
