20 Dr. Si the Rov. S. Graham Brade-Bhks— 



I »r. Kdfjar Newberv, now Professor of Physical Chcmistcy in 

 tlie Univcr>ity of Capetown, was Kind cnoufjh to expose 

 centipedes iVoni Kent, which were luininons when tested in 

 oilier ways, to the action of liadium, no Inrainosity of the 

 animals was |)rodnced. ^loreover, if luminosity was caused 

 hy the presence of radioactive substances, could the animals 

 control the appearance of light? Perhaps they could control 

 the chemical [)r(Kluction of a temporary screen. Even so, 

 why should luminosity die away so rapidly under all known 

 circumstances in its artificial production? There are some 

 questions here for physicists to settle. At any rate, we can 

 safely conchnle tiiat the liiiht is not due to the bombardment 

 of a permanent "screen" in the sternal region by the dis- 

 charge of a nidioactive substance in the excretion of the 

 " white glands." And also that, if a temporary " screen " is 

 jiroduced, it is the result of eheniical action, in which the 

 excretion from the " white glands ■' takes a part. 



Crysiallization. 



When G. carpophafpia is electrically stimulated under 

 water luminescence is induced much in the same manner as 

 in air. Tiicrefore crystallization, as Dubois (8) meant it, 

 is not the cause of luminosity in this species at any rate. 

 We have not yet proved that liquid crystals are absent. 

 The experiment of inducing phosphorescence l)clow water 

 also throws some doubt upon the conclusion of Dubois that 

 crystallization was the cause of the phenomenon in On/a 

 harharica. ^Moreover, we shall ol)serve almost immediately 

 in the present study that crystallization takes j)l:icc in the 

 mucin excreted bv the ventral surface of non-luminous 

 centipedes. 



Change of State. 



Tlie l)reakdown without chemical action of the solid 

 contents of a gland to form a liquid would absorb energy 

 and not emit it. 



(JZ/wr Physical Pussibilities. 



In the consideration of any purely jihysical cause, similar 

 objections arc likely to present themselves. It would appear 

 that new substances must be formed before physical phe- 

 nomena exhibit themselves, and we arc forced back upon 

 the conclusion that no jmreh/ phijsicdl caitac ir/i/r/i irc /tare 

 iiivt'sHf/alt'd serins adcijuiiti' to cri^lain tlir j>ru(iuction (if lujlU 

 tnj (ieojdiilns carpophagus. 



