36 BULLETIN OF THE BUSSEY INSTITUTION. 
finely powdered material were prepared from the wood of a pine 
tree three inches in diameter that was felled in Hingham, Mass., 
in the last week of August, 1900; from the wood of a tree 2.5 
inches in diameter felled in Hingham on December 14, 1901, and 
from white pine seeds bought of a Boston seedsman. Weighed 
quantities (25 grm. in each case) of the powdered woods were 
leached with four successive portions of cold water, then partially 
dried and washed with cold alcohol of 95 percent. Subsequently, 
the samples were soaked for two hours in a cold 2 per cent. solu- 
tion of caustic soda, and the soda was washed out with water 
with the aid of the filter pump. Each of the washed samples was 
boiled over a free flame during 4.5 hours in 250 cc. of hydro- 
chloric acid of 5 per cent.; the filtrate was neutralized with dilute 
soda lye (1:8), and to the clear filtrate there was added 20 cc. of 
a mixture of one part phenylhydrazin and two parts glacial acetic 
acid. After being allowed to stand for a couple of hours, the 
precipitated mannose-hydrazone was collected on a tared filter ; 
to the yellow filtrate more of the phenylhydrazin acetate was 
added, and the mixture was allowed to stand over night. A new 
precipitate of mannose-hydrazone formed, and it was collected on 
a new filter. Meanwhile, the residual wood left by the first 
hydrolysis was rinsed with water and treated again with 250 cc. 
of hydrochloric acid of 5 per cent. and boiled during 4.5 hours. 
The liquor was then neutralized and treated as before. No pre- 
cipitate of mannose-hydrazone formed in the course of an hour 
and a half, but after the mixture had stood over night a quantity 
of mannose-hydrazone was in evidence. This precipitate was 
collected on a new filter, a new portion of the reagent was added 
to the filtrate, and the small new precipitate that formed was 
collected in its turn. It was somewhat contaminated with crystals 
of dextrose-osazone. All these precipitates were washed with 
cold, distilled water, and subsequently with cold alcohol of 95 
per cent. to remove the osazone; finally, they were dried at 
100° C. and weighed. The residual wood was hydrolyzed for a 
third time by boiling it with 250 cc. of 5 per cent. hydrochloric 
acid during 4.5 hours, but no precipitate of mannose-hydrazone 
was obtained on testing the neutralized liquor. It hardly needs 
to be said that the method of estimating mannan above given is 
far enough from being perfect. It is not probable that all the 
