The Protein Components of Human Tears

Introduction  Recently McEwen and Kimura have employed filter paper electrophoresis to separate the proteins present in tears.¹ Their analysis showed the presence of at least three components in "normal" tears. One of these components was positively charged at pH 7.8 and was identified as lysozyme. Smolens, Leopold, and Parker,² studying tears induced by a lacrimating agent, benzyl bromide, report the presence of four electrophoretic fractions, three of which were basic at pH 7.9. Caselli and Schumacher report the presence of five electrophoretic fractions, only one of which was positively charged at pH 8.6.³In order to clarify this discrepancy, and in particular to study the effect of irritants, tears produced as a response to a variety of stimuli were studied.

Experimental Method  The tears were obtained from the conjunctival sac by the use of ultramicropipets of the Kirk type* (Fig. 1). In certain cases, notably with children