ADDITIONS AND NOTES TO YOLUME 



(1) Addition to p. 30, line 17- Colin* appears to have made 

 very extensive observations on the secretion of saliva in the solid- 

 ungula. Amongst other results of his investigations he mentions 

 that the secretion of the two parotids alternates, the parotid of the 

 side on which mastication is going on, secreting at least one-third 

 more than that of the other side ; and that when the masticatory 

 process is transferred to the other side, the activity of the first gland 

 very rapidly diminishes, and that of the second as rapidly increases. 

 He did not observe the alternating action in the secretion of the 

 submaxillary glands, which is apparently uniform on both sides. 

 When the animal consumes dry food, there are secreted from 

 5000 to 6000 grammes of saliva from all the glands in the course 

 of one hour; about l-3rd or l-4th more when the animal 

 consumes oats; and l-5th or l-4th less when living on succulent 

 roots. The parotids alone yield more than 2-3rds of the whole sum, 

 the submaxillaries only l-20th, and the sublinguals and mucous 

 follicles the remainder. The secretions of the parotid and submaxil- 

 lary glands occur almost solely during mastication, and for a short 

 time subsequently ; the thick and tough secretion of the other glands 

 of the buccal cavity, which remain moist during abstinence, amount 

 to only l-37th of the whole. The sight of food excites no per- 

 ceptible augmentation of the salivary secretion even in fasting 

 animals. 



Some very interesting experiments on the influence of the period 

 of secretion on the chemical constitution of the saliva, have been 

 made by Becher and Ludwig.f They found that the solid residue 

 of the saliva diminishes in proportion to the amount which the 

 gland has already yielded ; the organic constituents sinking far 

 more rapidly than the inorganic. Fluctuations in the quantity of 

 water in the blood did not disturb this law, as was proved by the 

 examination of saliva collected after one or more venesections ; nor 

 was it affected by the injection of chloride of sodium into the blood, 



* Compt. rend. T. 34, pp. 327-330. 



t Zeitschr. f. rat. Med. N.F. Bd. 1, S. 480-483. 



