288 CARNEGIE INSTITUTION OF WASHINGTON. 



melting-points of binary and ternary mixtures of all the five alkali 

 chlorides were obtained with a degree of precision which left nothing 

 to be desired. The relation between the eutectic points of these 

 mixtures is especially interesting. 



A number of papers concerning previous investigations were pub- 

 lished during the year; their titles will be found in the Bibliography, 

 p. 53. 



Sherman, H. C, Columbia University, New York, N. Y. Grant No. 850, 

 allotted Dec. 13, 1912. Continuation of the chemical investigation of the 

 aymjlases. (For previous report see Year Book No. 11.) $1,200 



During the year this investigation has been continued according 

 to the general plan outlined in the report for 1912, special attention 

 being given to the purification of malt amylase and the study of the 

 chemical nature of the amylase preparations from malt and from the 

 pancreas. Preparations of much higher enzymic activity than had 

 been reported by previous investigators have been obtained and such 

 preparations both from malt and from pancreas have been clearly 

 shown to be of protein nature, yielding the typical forms of amino 

 acid nitrogen on hydrolysis. The chief features of the work of the 

 j-ear may be briefly described as follows : 



Much time has been devoted to the purification of malt amylase 

 with a view to the development of a method capable of yielding a 

 uniform product of maximum activity corresponding to the pan- 

 creatic amylase previously described . By procedures varied in detail , 

 but in principle based partly upon Osborne's method for malt and 

 partly upon our method for pancreatic amylase, 38 experiments in 

 purification have been made, of which 34 have yielded products of 

 greater activity than previously described for malt amylase; 7 of 

 these have shown from three to four times the diastatic power of the 

 most active preparation reported by previous investigators; 29 

 other purification experiments made by essentially different methods 

 have yielded much less active products. Since the best preparations 

 thus far obtained from malt are less uniform in activity than those 

 obtained from the pancreas, the study of methods of purification is 

 being continued. 



The active amylase preparations obtained from malt correspond 

 in general properties with Osborne's description of malt diastase 

 published in 1895-96 rather than with the descriptions of some of 

 the more recent investigators. The material is a yellowish-white 

 solid approaching the typical proteins in nitrogen content and show- 

 ing typical protein color-reactions and the appearance of a colloid 

 under the ultramicroscope. When heated in water solution it coag- 

 ulates; the coagulum gives a violet-blue, and the filtrate a rose-red, 

 biuret reaction. Since this material, like the pancreatic amylase, 



