[Vou. 2 
790 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
This was brought to a boil with constant stirring, and when 
an opalescent solution resulted the paste was transferred with 
rinsing to a 2-liter flask containing about 500 ec. of boiling 
water. The lot was boiled under a reflux condenser for two 
hours, cooled, and made up to a liter. Although, as is stated 
by Clark, this treatment is very effective in breaking down 
the starch grain physically, no detectable hydrolysis: takes 
place, and the additional advantage is gained in obtaining a 
paste that will not settle out, even after long standing. Two 
per cent toluene was employed as an antiseptic if the starch 
were not to be used immediately. 
Since all dextrin obtainable contained some reducing sugar, 
it was found necessary to purify it by making a concentrated 
solution in hot distilled water, and then precipitating out with 
several volumes of 95 per cent alcohol. The dextrin was 
caught on a filter paper and dried at a low constant tem- 
perature. 
Laminarin, a dextrin-like carbohydrate found in many of 
the Fucaceae, was isolated from Laminaria Agardhu accord- 
ing to the method employed by Kylin (713), with some few 
slight modifications. Freshly collected Lamimaria was 
crushed in the usual way and 1,680 grams of the pulp were 
boiled with 7 liters of water for 24 hours, water being added 
from time to time to replace that lost through evaporation. 
The extract was then filtered off through a double thickness of 
cheese cloth, and the residue pressed out with a tourniquet. 
About 3,000 ec. of a dirty brown filtrate were obtained which 
was divided into three lots of 1,000 ce. each. To the first of 
these was added a concentrated Ba(OH)2 solution until the 
precipitation of the inorganic matter was complete. The pre- 
cipitate was caught on a cotton filter in a Buchner funnel, 
the filtrate being a clear, golden-colored liquid. The inorganic 
material in the other two lots was precipitated with basic 
lead acetate, the liquid filtered off through cotton, and the 
excess of lead removed with H28. The solutions were filtered 
while hot through double filter paper to remove the lead 
sulphide, and then the excess of HS was driven off with 
heat. The three portions were first evaporated to about one- 
