246 E. I. WERBER. 



the iris be removed by cutting (iridectomy) without removing 

 the lens, the iris will regenerate but form no lens-like structures. 

 \Yachs (/. c.) attempted to account for this fact by the assumption 

 of a secretion from the lens which would inhibit the formation 

 of another lens. The results of some of his experiments, he 

 believes, substantiate this conclusion. In these experiments the 

 lens was removed and subsequently the lens of another animal 

 of the same or a related species was introduced into the eye. In 

 no case in which the foreign lens healed into the eye was a lens 

 "regenerated." This result, however, permits of another inter- 

 pretation, in which no resort is made to the improbable assump- 

 tion of the "antisecretion" by the lens. 



Indeed,Wachs'sown ingenious experiments performed for the 

 solution of this particular part of the lens-problem would seem to 

 disprove rather than to prove the assumption of a secretion. For 

 they show that the "regeneration" of a lens is inhibited only 

 when the (smaller) lens implanted into the eye, heals into it, i. e., 

 comes into close contact with the iris ("so dass die verengerte 

 Iris sich ihr ringsum dicht anschliesst . . . ," p. 404). If, how- 

 ever, such contact is not effected "liegt jedoch die aus dem 

 jiingeren Tiere implantierte kleinere Linse mehr oder weniger in 

 der vorderen oder hinteren Kammer, so w'rd eine Regeneration 

 eingeleitet." 



Wachs has ascertained beyond doubt that the inhibition is in 

 these cases due not only to the mechanical effect of the contact, 

 but very apparently also to a chemical action. While, however, 

 he strongly inclines to the belief that the chemical action is due 

 to a secretion, I think it can easily be shown also in all other of his 

 experiments by which the matter was tested, that this chemical 

 action is conditioned by contact of the implanted lens with the iris. 



These important experiments of Wachs, strengthened further 

 by some interesting results of Fischel's ('02) experiments 1 would 



1 Fischel exstirpated the lens and replaced it by small spherical fragments of 

 the potato tuber. Whenever this "imitation lens" was large enough to fit the 

 pupilla, no "regeneration" of a lens from the latter took place. If, however, its 

 diameter was smaller than that of the pupilla, partial "regeneration" of the lens 

 or at least an "attempt" towards it was noted, complete "regeneration" being 

 impossible owing to mechanical obstruction by the potato fragment. This experi- 

 ment clearly demonstrates that the extraction of the lens eliminates not an in- 

 different body, but one with a specific, inhibiting, action. 



