ADAPTATION OF PANCREAS 97 



order to destroy any lactase which might be present. Exactly equal 

 volumes of each were then treated with the same bulk of 5 / lactose 

 solution, and 2 /o f toluol added. The mixtures were then incubated at 

 38 C. in corked bottles for periods varying from one to three days. As 

 is well known the pancreatic juice is strongly alkaline. In the first 

 experiment therefore the sample was taken at the end of 24 hours, and 

 the remaining mixture of juice and lactose was neutralised and allowed 

 to incubate for a further 24 hours. 



In the third experiment the whole of the pancreatic juice was 

 neutralised at the commencement of the experiment by means of hydro- 

 chloric acid, and was then treated as already described. The kitten was 

 about 5 weeks old and had been about a fortnight away from its mother, 

 but had received milk during the whole time. 



The two mixtures after being incubated for the various times were 

 treated with 10 c.c. of mercuric nitrate solution, prepared in the manner 

 described by Patein and Dufau (7) . After allowing to stand for about 12 

 hours, in order that the precipitates should settle, they were filtered and 

 the same quantity of the filtrate of each was neutralised with the same 

 amount of 10 per cent, caustic soda. By this means most of the mercury 

 was precipitated as oxide, the filtrate from this precipitate containing 

 only small traces. Exactly equal quantities of the filtrates were then 

 treated with hydrogen sulphide to remove the last traces of the mercury, 

 and the excess of hydrogen sulphide was removed by means of copper 

 sulphate solution. The solutions were then made up to a definite 

 volume, generally 250 c.c. and filtered. The faintly acid filtrates, so 

 obtained, were then employed for determining the rotatory power in a 

 2 decimetre tube and the reducing power by Allihn's method, the 

 cuprous oxide being collected on a modified Soxhlet filter as described 

 by Plimmer and Bay liss (8) , washed with alcohol and ether, dried at 

 110 C. and weighed. In every case at least two determinations of the 

 cuprous oxide were made, and since these differed only by about 2 milli- 

 grammes in weight, the reduction to copper or oxidation to cupric oxide 

 was not carried out. 



In order that there should be the least possible error in all these 

 processes the same pipettes were used throughout. They were always 

 thoroughly cleansed, and dried with alcohol and ether before the liquids 

 were taken up into them for measurement ; only when the mixtures were 

 finally made up to a definite volume, different measuring flasks were 

 employed, otherwise the volumes taken from each solution were always 

 exactly the same. By this means a perfect control experiment was made. 



