1879.] 



Researches on Lactin. 



211 



same law throughout, but that, at the point referred to, a new reaction 

 begins. This value of y is proportional to the amount of lactin in 

 solution, indicated by the permanent rotation ; and the specific rota- 

 tion calculated from it in the different experiments is practically 

 constant, its average value (from twenty experiments) being 64° - 8. 



dx 



The following are the values of x and y when 



:0. 



Table III. 



No. 



X. 









o 



2 ... 



. . . 16 -029 . . . 



9-571 



















10 "214 













10 '552 



o 







9 



. .. 16-666 ... 



11 -045 



10 , . 



. . . 15 -388 . . . 



10 -178 



11 



. . . 15 -292 . . . 



10 -315 



12 



. .. 14-217 



10 -622 



13 



... 16-225 ... 



12 -920 



14 



. .. 15-855 ... 



11 -461 



15 



... 15-776 ... 



, 12 -133 



16 



... 17-898 ... 



10 -319 



17 



... 15-804 ... 



11 -149 



18 



... 14-772 ... 



11 -622 



19 , 



. . . 18 -199 . . . 



, , 12-250 



20 



. . . 18 -836 . . . 



. . . 10 -624 



Specific rotation. 



o 



66 



•71 



66 



•14 



64 



•95 



63 



•42 



65 



•11 



63 



•31 



63 



•91 



65 



•63 



63 



•22 



64 



•20 



66 



•39 



63 



•53 



64 



•88 



63 



•57 



64 



•78 



65 



■41 



65 



•06 



63 



•79 



66 



•36 



65 



•71 



This break in the change seems to point to the dual nature of lactin 

 mentioned by Fudakowski,* whose experiments show that lactin, like 

 cannose, gives two glucoses — lacto glucose and galactose. 



An increase of temperature evidently hastens the change ; but the 

 exact relation of temperature to the rate of change has not been dis- 

 covered. 



The presence of sodic or potassic chloride increases the amount of 

 lactin in solution, but has no apparent effect on the rate of change. 



IV. Action of Hydric Nitrate on Lactin. — We made an attempt to 

 trace this action, but did not succeed in overcoming experimental 

 difficulties. The first of these was the impossibility of completing the 

 action with the quantity of acid required for the first change. If a 



* " Deut. Chem. Ges. Ber.," ix, 42-44. 



