G. Williams 213 



Tryptophan. 



The protein gave the glyoxyhc reaction showing the presence of 

 tryptophan. 



Cystine. 



The protein gave the sulphur reaction with strong soda and lead 

 acetate, showing that cystine is probably present. 



Summary. 

 The results of the hydrolysis are given below : 



PAGE 



Glycine 0-27 per cent. 198 



Alanine 3-58 „ 204 



Vahne 9-95 „ 206 



Leucine and Isoleucine 9'01 ,, 205 



Phenylalanine 4-47 „ 197 



Tyrosine 2-92 „ 212 



Cystine present 213 



Prohne 4-17 per cent. 196 



Aspartic acid 6-98 „ 210 



Glutaminic acid 3-18 „ 210 



Tryptophan present 213 



Arginine 3-12 per cent. 188 



Histidine 3-04 „ 187 



Lysine 4-35 „ 188 



Ammonia 1'21 „ 185 



Humin bodies 4-74 .. 189 



60-99 



Remarks. 



Levene and Van Slyke's method for the separation of alanine and 

 vahne seems to be a valuable one. AVhen pure chemicals are used, 

 pure alanine and pure vahne can be obtained. Pure valine only was 

 obtained in this case, the alanine being contaminated mth ash owing 

 to the impurity of the phosphotungstic acid used. The greatest draw- 

 back is the large amount of acids which is lost in the precipitates of 

 lead sulphate and phosphotungstate. The fact that the approximate 

 composition of the mixture must be determined before the apphcation 

 of the method also militates against its usefulness. This method. 



