562 ERICH SACHS AND REUBEN L. LARSEN ficient strength in the aqueous, it would still have to penetrate the lens capsule in order to reach the lens proper. The capsule proн vides another barrier because it permits difн fusion only at a very slow rate. If the permeability of the capsule deн creases with advancing years (as assumed by several authors1), age, generally promoting development of cancer, would exert an adн verse influence in the lens. Solubility. The aqueous is a true watery solvent and is practically devoid of colloids, protein, and fat. 2 The majority of carcinoн gens studied so far are water-insoluble. Hence a carcinogen belonging to the group of water-insoluble agents could not reach the lens.

Secondary aqueous. The physiologic propн erties of the aqueous change radically after tapping the anterior chamber. The secondary aqueous, formed after draining off the priн mary, resembles blood plasma in many reн spects. By applying this technique, it should be experimentally feasible to expose the lens to known carcinogens in adequate concentraн tions, and thus learn how the lens reacts to a carcinogen when contact is actually made.