PHYSIOLOGY OF THE INVERTEBRATA. 



107 



In the aqueous extract 



/ Sugar 

 Globulin (coagulating at 66° C.) 

 Glycogen 

 Sinistrin 

 Hypoxanthiue * 



f Potassium 

 Sodium 

 Calcium 

 Magnesium 

 Ash ( Iron (traces) 

 Manganese 

 Chlorine 

 Phosphoric acid 

 \ V Sulphuric acid. 



In winter animals, silica was also found as an ash con- 

 stituent. 



Dr. Fredericq has investigated the nature of the secretions 

 of the salivary glands and " liver " of Avion rufus. The 

 secretion of the salivary glands readily acts upon starch, but 

 has no action upon fibrin and neutral oils. The secretion of 

 the "liver" is a brown liquid, and can be collected in a 

 sufficiently large quantity by killing a large number of fresh 

 snails. It suffices to dissect them lengthways to extract the 

 viscera, and tO collect the liquid which flows from the cut end 

 of the intestine. If the secretion is extracted after the ani- 

 mals have just been feeding, it is most likely that the secretion 

 will be slightly acid (acidity due to food) ; in that case the 

 digestion of fibrin takes about twenty-four hours. On the 

 other hand, if the secretion is extracted when alkaline, or if 

 the acid secretion is rendered slightly alkaline by a small 

 quantity of sodium carbonate, its activity is greatly increased. 

 In an acid solution the ferment is inactive, and this is readily 

 observed when a small quantity of acidulated water is added 

 to the digestive fluid of the snail, for it completely stops the 

 digestion of fibrin. 



The " liver " and its secretion furnish a diastatic f ernient 

 trausforming starchy matters into glucose. The so-called 



* And other bases preoipitable by phosphotungstic acid. 



