TENSION PHKN'iMI NA OF LIVING ELEMENTS. l6l 



these sub-tances enter the fertilized eggs more easily). The 

 same explanation may po--ibly he applied to the effect of sugar 

 on ten. tin living cells. The- unfertilized eggs of the frog, petro- 

 niyzon, sea urchin and annelid have been caused to segment, 

 by placing them in sugar Dilution-. Mayerhofer and Stein 1 ob- 

 . <'! that sugar in certain concentrations increased the per- 

 meahility of the gut to certain -.ill-, ami in this condition the 

 ytn was more easily injured by the diffusion of substances. 



similarly Mockard obser\ ed that sugar increased the toxicity 

 "t pun- -oliitions of salts on the Fundulus egg. Morgan and 

 stiH k.nd -hi.ued that ih\< \\a- not dm- to the inversion of sugar 

 or to thr o-motic pressure, and suppn-ed that the sugar might 

 combine chemically with the -alt. It >cems probable that the 

 ii increased the permeal.ilitx t" -.ilt. The fact that sugar 

 in Ire-h \\ater is toxic whena- the -amc amount of sugar in 

 tin- nimal medium (sea water Uimt toxic or less toxic, indicates 

 that tin- -alts within the l-'nndidit are the same as those 



out-idi- in sea water), and iiicrea-e in permeability to them 

 d'<-- nut lead to diffusion while they remain in sea water, but 

 diltii>ioii takes place in fresh \\ateiv 



It it In -liiiun that cancer cell- are MHHV permeable,' substances 

 Mia\ he toiiml which kill cam er cell- mure easily than tissue 

 i (II- as i \pl. lined below. 



\\liena- a certain men .i-e in j HTMU -ability of the cell seems 

 in cau-e di\i-imi, a very :^reat iih in permeability causes 



death h. i nicK -is, cytoK -i-. hai terii il\ <i- ' . It has been shown 

 that certain l\ -ins are spt cilic t'm- certain cells, probably because 

 the pla-iiia Mieinhraiie- of ilu-e cells differ chemically. 



I In- fertili/ed e-- is more easily c\ t|\ /od than the unfertilized 

 i tain -lib-lances. It then-tore appears that the more 

 peimeable the cell is in the beginning, the more easily is the 

 IH i ineahiliiN brought to the point \\hit-hcausescytolysis. 



1 It nee ii i- pmhahle that certain substances may be found by 

 \\ hich cancer cell- tan 1 e nn >\ e ea-ily cytolvzcd than normal tissue 

 cells. 



n. /.fit.. 1910, \\V1I.. 376. 



- BIOL. r.i M .. [907, xiii.. - 



3 In tin .il -IIU.H I have -tiown that no diffusion take3 place in fresh 



\\.iu-r. Am fr. Jour, i \.XIX.. 295. 



