1922]  Grier,—Preserving Indian Pipes without Discoloration 225 
PRESERVING INDIAN PIPES WITHOUT 
DISCOLORATION. 
N. M. Grier. 
Ir will be recalled that with the usual procedure Monotropa turns 
black when pressed or preserved in alcohol or formalin. While 
engaged at the Biological Laboratory, Cold Spring Harbor, New York, 
during the past summer, the writer developed methods of preservation 
of these plants which to the present time have yielded very satis- 
factory results. The success of certain of the following methods is 
largely due to the suggestions of Dr. Oscar Riddle of the Carnegie 
Institution of Washington. 
The post mortem blackening occurring in these plants is, according 
to the best authorities, due to the action of an oxidase upon the 
protein resulting in the formation of melanin pigment. With this in 
mind, the steps in the methods now given will be better understood. 
Specimens should be well washed in cold water, and punctured at 
intervals along the stem and inflorescence with a fine needle. They 
should then be just immersed in boiling water and removed immedi- 
arely, as a lengthened period of immersion results in a blackening not 
removed by subsequent chemical treatment. The specimens are then 
placed in any one of the following solutions for permanent preservation 
without discoloration. 
1. Carnoy’s fixing fluid, made up on the basis of 95% alcohol 
rather than absolute. Punctured specimens, preserved without 
boiling in this solution, remained an excellent color. This fluid gave 
better results than any other used. 
2. 95% alcohol, to which has been added 10% by volume of con- 
centrated hydrochloric acid. In a few days, such a solution acquires 
a beautiful ruby hue from the pigment it has dissolved and precipit- 
ated. It should then be changed, lest the specimens acquire such 
coloration. Two or three changes of this fluid at intervals are suf- 
ficient. The specimen may then be kept in the final change, although 
the acid may be dispensed with. If punctured specimens with or 
without the boiling treatment are kept in 95% alcohol alone, an 
equally beautiful blue pigment is dissolved and precipitated. The 
reaction of the pigment to these chemicals resembles that of hema- 
toxylin to acids and alkalies. 
