The excerpt represents the core issue or deciding factor on which you must meditate, and is drawn from Expression of Emotion in Man and Animals by Charles Darwin:|
Notwithstanding these latter cases, it seems hardly credible
that the pressure of the eyelids on the surface of the eye,
although effected spasmodically and therefore with much greater
force than can be done voluntarily, should be sufficient to cause
by reflex action the secretion of tears in the many cases
in which this occurs during violent expiratory efforts.
 See, on these several points, Prof. Donders `On the Anomalies
of Accommodation and Refraction of the Eye,' 1864, p. 573.
Another cause may come conjointly into play.
We have seen that the internal parts of the eye, under certain
conditions act in a reflex manner on the lacrymal glands.
Expression of Emotion in Man and Animals