-2l- AECD -3446 amperature of 100° - 300°C, caution being exercised to avoid bubbling and g The plates of dried tissue were then transferred to muffle furnaces ‘her ashing at carefully controlled temperatures of 500 - 550 (rarely 600) to, a white ash which required from 2 to 5 hours. ess. No acid was used in Mean net weights and standard errors of ashed tissues were fast tube ‘and then mixed by vigorous shaking. Using a pipette, from 2 to 5 cc. of themixture were transferred to a counting plate that had been previously flamed “sabi wetched. Flaming of the plate toaa cherry red color over a gas burnerre- - Yinches.”: The plate : with the mixture was placed under an infrared heat lamp, te tmixture was allowed to evaporate to dryness, and the plate was removed be- eo a.sakBary sample began to crack from over-heating. After the plate had c.,‘the plate and sample were weighed and the original plate weight sub= pe ito determine weight of ash on plate. The mean weight and standard the ash on the 2-inch counting plates were 0.08 + 0.01 grams which is enng of samples were written on the sides of the porcelain dishes and 2 ied On the bottom of the stainless steel plates. Occasional samples, _ ae than one-half of one percent, cracked or crumbledandfailed to ably bealliage -