Practical physiological chemistry; a book designed for use in courses in practical physiological chemistry in schools of medicine and of science . apo-rated. The drying is continued in a hot-airoven at a temperature below loo^C. and finallycompleted in a desiccator to constant weight. CroUs modification consists of subsequentrepeated extraction of the end-product ofevaporation with absolute ether. The com-bined extracts are filtered and the small filter paper is washed repeatedly with absolute ether. The combined extracts andwashings are evaporated and dried as before and then weighed. The pie
Practical physiological chemistry; a book designed for use in courses in practical physiological chemistry in schools of medicine and of science . apo-rated. The drying is continued in a hot-airoven at a temperature below loo^C. and finallycompleted in a desiccator to constant weight. CroUs modification consists of subsequentrepeated extraction of the end-product ofevaporation with absolute ether. The com-bined extracts are filtered and the small filter paper is washed repeatedly with absolute ether. The combined extracts andwashings are evaporated and dried as before and then weighed. The piece of apparatus shown in Fig. 107, above was also devised by Crollto do away with the use of the pipette. ^ On closing the top with a finger andblowing into the mouthpiece, the upper stratum is forced out into the dish. Thebottle is washed by simply pouring the ether into the tube. This lessens thepossibility of accidental loss. ^ Original paper by Dr. .Arthur V. Meigs in Philadelphia Medical Times, July i, 1882.^ Croll: Biochem. Bull., 2, 509. 1913. If desired a cork with two tubes may be substituted for this somewhat Fig. 107.—Crolls Fatajppar.\tus. 326 PHYSIOLOGICAL CHEMISTRY The accuracy of the method compared with that of the Soxhlet method,using the paper-coil modification and extracting until fresh portions of absoluteether gave no further trace of extractive material, is shown by the average difference on twelve samples of human milkbeing only per cent less than by theSoxhlet and on seven samples cows milk beingonly per cent less. The extreme differ-ences in case of the hrnnan milk were— cent and— per cent and in case ofthe cows milk— per cent and— percent. (f) Adams Paper-coil Method.—Introduceabout 5 of milk into a small beaker, quicklyascertain the weight to centigrams, stand a fat-free coU^ in the beaker and incline the vesseland rotate the coil in order to hasten the absorp-tion of the milk.
Size: 1016px × 2459px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectbiochem, bookyear1916
