278 PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



sediment of calcium carbonate. When allowed to slowly evaporate on a 

 glass plate, crystals of sodium chloride and calcium carbonate are formed. 

 It is said to contain no diastatic ferment. 



The parotid saliva of the horse contains large quantities of lime, and 

 when allowed to stand in the air deposits beautiful crystals of the car- 

 bonate of lime. The parotid saliva is largest in amount ; the two glands 

 of the ox are said to produce in an hour eight hundred to twenty-four 

 hundred grammes of saliva. As already stated, this secretion is inter- 

 mittent in the horse and constant in ruminants, where it is closely con- 

 cerned in the phenomena of gastric digestion. 



The diastatic action of the parotid saliva is very active in rodents, 

 but little active in ruminants ; absent in the sheep, though in the latter, 

 animal, as in the case of the horse and ass, watery infusions of the parotid 

 salivary glands will convert starch into sugar. In carnivora the parotid 

 gland is relatively smaller in amount and is almost inactive. 



The following analyses have been made of parotid saliva: — 



Man. 



Water, 993.16 



Solids, .......... 6.S4 



Organic matter 3.44 



Chlorides and carbonate of lime, 3.40 



Bog. 



Water, . . . ■. ■ . , •. ... . 995.3 



Solids, 4.7 



Organic matter, . . . . . . . . 1.4 



Potass, sulphocyanide and alkaline chlorides, .. . 2.1 



Calcium carbonate, . 1.2 



Horse. 



Water, 992.92 



Solids 7.08 



Epithelium and calcium carb 1.24 



Soluble matter, 5.84 



Alcoholic extractives, 0.98 



Soaps, 0.43 



Cow. 



Water 990.7 



Mucin and soluble organic matter, .... 0.44 



Alkaline carbonates, 3.38 



Alkaline chlorides 2.85 



Alkaline phosphates 2.49 



Calcium phosphates, 0.10 



Bam. 



Water 939.0 



Mucin and soluble organic matter, .... 1.0 



Alkaline carbonates, 3.0 



Alkaline chlorides, 6.0 



Alkaline phosphates 1.0 



Calcium phosphates, \ traces. 



