Mercer's company lectures on recent advances in the physiology of digestion . duct was free-(Bunch). A primary increased transudation of lymph would cause aninitial expansion in the volume of the gland, and we mustconclude, therefore, that the first effect of stimulation is noton the blood-vessels, but on the secreting cells of the alveoli,causing them to empty out their contents, including solidsand water. Only later can the cells recoup themselves atthe expense of an increased transudation from the blood-vessels. This loss of gland substance is indicated by the figures I SECRETION OF SALIVA.
Mercer's company lectures on recent advances in the physiology of digestion . duct was free-(Bunch). A primary increased transudation of lymph would cause aninitial expansion in the volume of the gland, and we mustconclude, therefore, that the first effect of stimulation is noton the blood-vessels, but on the secreting cells of the alveoli,causing them to empty out their contents, including solidsand water. Only later can the cells recoup themselves atthe expense of an increased transudation from the blood-vessels. This loss of gland substance is indicated by the figures I SECRETION OF SALIVA. 55 have quoted above on the changes in the weight and in thepercentage of solids of the gland during secretion. The sameconclusion is borne out by Pawlows estimations of the amountof nitrogen in secreting and resting glands respectively. Thisobserver found that, whereas ten resting glands contained2#18 gr. of nitrogen, ten glands from the same animals, whichhad been stimulated for some hours, contained only 1*872 nitrogen, representing a loss by these glands during. Fig. 5.—Tracing of volume of submaxillary gland, showingeffect of chorda stimulation after obstruction of the will be noticed the volume diminished as soon as theduct was released, so as to allow the saliva to flow away. secretion of 308 gr. of nitrogen. The saliva obtainedduring these experiments yielded *416 gr. of nitrogen, sothat the glands had taken up only 19 gr. of nitrogen (,£j of the total amount) from the blood passing through the primary result of stimulating the secretory nerves is tocause the gland cells to discharge their organic matter togetherwith water and salts. The cells then recoup themselves atthe expense of the blood circulating through the blood-vessels;but this process, although practically complete in the case of 56 THE PHYSIOLOGY OF DIGESTION. the water and salts, is very inadequate in the ease of thenitrogenous constituents of the cells, which have been lost
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