ESSAYS 303 



Lossky's appeal to ontology for help admits the seriousness of his episte- 

 mological trouble. If his difficulty with time and space is resolved for 

 him, he has still to explain one very important difference between remem- 

 bering a perceived object and reperceiving it. The memory image cannot 

 be further differentiated ; the object can be further differentiated if the 

 knower again becomes its percipient. An observer casually perceives a 

 wayside cross without noticing a small red mark at its foot. Repeated 

 inspection of the memory image leaves the mark still unobserved and un- 

 differentiated. Another look at the cross may instantly reveal it. " Re- 

 iterated differentiation of objects," to which Lossky ascribes the " clearing 

 away of falsity," ^ is possible in perceiving and reperceiving objects in a 

 way in which it is not possible by reference in memory. 



Our general mental reaction in actual perception is too different from 

 our general mental reaction in memory to allow of Lossky's homogenisation 

 of percept and memory image. Memory images impressed upon minds by 

 objects external to the knower explain, far more simply and consistently 

 than Lossky's intuitive apprehension of immanent objects, the familiar 

 phenomena of perception and memory. One object or event may affect 

 many knowers, as one candle can shine on many mirrors. One object 

 unified with many subjects is a much less intelligible conception : many 

 percipients, it should be remembered, can perceive the same object without 

 any awareness of one another's percipience. The requirement of appro- 

 priate situation for percipience is intelligible without requiring Lossky's 

 drastic ontological revision of space and time. The memory image dis- 

 credits the perceptual object's claim to immanence in knowledge by its own 

 greater claim on that role. As a mental method of reference to the original 

 event or object, the memory image impressed by the original perception is 

 naturally independent of locality or time. As a register of differentiation 

 achieved during perception of the object, the memory image is also naturally 

 unpermissive of further differentiation that can only be secured by a reper- 

 cipience, subject, like the original percipience, to strict conditions for the 

 situation of the knower. 



RECENT WORK ON THE INFLUENCE OP THE DUCTLESS 

 GLANDS UPON AMPHIBIAN METAMORPHOSIS (Lancelot 

 T. Hogben, M.A., B.Sc.) 



While research in many fields has been necessarily curtailed by the events 

 of the past six years, considerable progress has been made in the study of 

 the endocrine organs. One noteworthy advance is due to Kendall (igi8), 

 who has isolated thyroxin, the physiologically active iodine compound 

 present in the thyroid gland ; and has established its constitution as trihy- 

 droxy-triodo-oxy ^-indole propionic acid. On the experimental side, several 

 new lines of inquiry have been opened up by the discovery of Gudernatsch 

 (191 4) that it is possible to accelerate metamorphosis in tadpoles by means 

 of a diet of mammalian thyroid. The peculiarly favourable conditions of 

 experimentation afforded by the study of amphibian metamorphosis have 

 naturally given an impetus to the investigation of the influence of the ductless 

 glands along these lines. 



Gudernatsch's method of inducing a precocious transition from thelarval 

 to the adult condition in the case of frog and toad tadpoles has been abun- 

 dantly confirmed by the work of Morse, West, Barthelemez, Lenhart, and 

 Swingle. In Swingle's experiments the metamorphosis of tadpoles of Rana 

 cateshiana, a species which normally reouires two or three seasons to attain 

 the adult state, was accomplished, by means of a thyroid diet, within a single 



^ The Intuitive Basis of Knowledge (Duddington's trans.), p. 230. 



