36 Mr. F. A. Bainbridge. [May 25, 



The extracts of intestinal mucous membrane were made by scraping 

 the gut after washing away all food debris ; the gut was ground up 

 with sand, and extracted with chloroform-water, lactose solution, or 

 tap-water. The extracts were then filtered through muslin, and either 

 injected at once, or kept in an ice-chest until they were required. 



-Results. The samples of lactose, galactose, and dextrose which I 

 used, had the following reducing powers on Pavy's solution, taking 

 dextrose as 100. 



Pure lactose 52 -0 



Lactose inverted with hydrochloric acid ... 88*5 



Pure dextrose lOO'O 



Pure galactose 87*4 



The theoretical value of inverted lactose is therefore 93 -7, but I 

 never succeeded in obtaining this figure by even prolonged boiling of 

 lactose with acid. 



I. The pancreatic juice was first examined in dogs kept for some 

 days in the laboratory, and fed on biscuits only. In such dogs no 

 lactose was ever found. The following protocol illustrates a typical 

 experiment : 



Experiment I. Dog fed on biscuits only for 2 weeks 

 The dog was anaesthetised with morphia and A.C.E. mixture, and 

 pancreatic juice collected by means of secretin. 



Pure lactose solution, strength 3*640 per cent. 

 (a.) 25 c.c. pure lactose solution, diluted to 200 c.c. and titrated. 



10-2 c.c. = 50 c.c. Pavy's solution. 

 (b.) 25 c.c. lactose solution -| 



2 c.c. pancreatic juice I Incubated at 37 for 72 hours. 



Few drops CHC1 3 J 



Neutralised with acetic acid, boiled, filtered, and made up to 

 200 c.c. 



10-4 c.c. = 50 c.c. Pavy's solution. 



II. Dogs fed on milkWhen dogs were fed on milk, to which 

 lactose was added in some cases, their pancreatic juice invariably 



contained lactase, and an inversion of lactose, varying from 12 30 



per cent., occurred in different cases. A table of the different experi- 

 ments and a protocol of one of them illustrates this point : 



