342 CHEM1STR Y OF THE DIGESTIVE PROCESSES. 



fluid, aided by the presence of free fatty acid in the fat used for the 

 experiments. 1 



Paschutin 2 attempted by two different methods to separate the 

 diastatic and inverting ferments : 



1. An infusion of the intestinal mucous membrane was made by rubbing 

 it up with water and powdered glass, and filtering. When this infusion was 

 mixed with a solution of collodion, the precipitated collodion brought down 

 most of the inverting enzyme, and most of the diastatic enzyme was left in 

 solution, but only a partial separation could be effected in this manner. 



2. The mucous coat of a piece of intestine was freed from the other coats, 

 and then water was filtered through this, under pressure. The fluid which 

 filtered through acted energetically on starch, but had no action or only a 

 very feeble one on cane-sugar. 



THE CHEMICAL COMPOSITION OF THE DIGESTIVE 

 SECRETIONS. 



SALIVA. 



The saliva is a mixture in varying proportions of the secretions 

 of the different salivary glands. As these secretions differ from 

 one another considerably in chemical composition, it will be well 

 to consider first the physical and chemical nature of each of them 

 in turn, and afterwards that of the fluid which results from their 

 admixture. 



Submaxillary saliva. Submaxillary saliva may be obtained by in- 

 serting a fine cannula into the opening of Wharton's duct. In some 

 individuals Wharton's duct carries to the mouth the secretion of the 

 Submaxillary gland only, in others the duct of Bartholin leads into 

 Wharton's duct, when the latter conducts the mixed secretion of the 

 Submaxillary and sublingual glands to the month. The tongue should 

 be raised, but not too high, the cannula carefully inserted and gently 

 pushed into the duct for about an inch. By this procedure the end of 

 the cannula is thrust past the opening of the duct of the sublingual 

 gland, in case both glands share a common duct, and so the obtaining of 

 Submaxillary saliva only is ensured. 3 



Human snbmaxillary saliva is a clear, watery, mobile fluid, which 

 becomes viscid on standing in contact with air, and deposits flocculi. 

 It is always alkaline in reaction. On boiling, it becomes cloudy, and 

 the cloudiness is increased by the addition of acid. Its specific gravity 

 varies between 1'0026 and 1*0033, and is lessened by hunger. The 

 amount of total solids lies between 0'36 and 0'46 per cent., and is not 

 much influenced by food. According to Eckhard, it contains no 

 sulphocyanates, while Oehl and Sertoli 4 state that it contains them, 

 but in less amount than the secretion of the parotid. Colorimetric 



1 See, however, Schiff, Arch, de physiol. norm, ct path., Paris, 1892, tome xxiv. p. 679. 

 Schiff here repeats his earlier statements, that succus entericus acts both on proteids and 

 neutral fats. Prege (Arch. f. d. ges. PhysioL, Bonn, 1896, Bd. Ixi. S. 359) has recently 

 obtained succus entericus from a Vella fistula in the sheep, and determined that it has no 

 action on proteids or neutral fats. 



2 Arch. f. Anat. u. PhysioL, Leipzig, 1871, S. 305. 



3 Eckhard, Jahresb. it. d. Fortschr. d. ges. Med., Erlangen, 1862, Bd. i. S. 126 ; cited 

 from Maly, Hermann's " Handbuch," Bd. v. (2), S. 17. 



4 Oehl, Jahresb. u. d. Fortschr. d. ges. Med., Erlangen, 1865, Bd. i. S. 120 ; Sertoli, 

 ibid., 124. 



