RESISTANCE OF CILIA TO CYTOLYTIC AGENTS. 427 



Thus resistance of cilia to both saponin and hypotonic NaCl 

 is lowered by increasing temperature instead of remaining con- 

 stant as is the case with erythrocytes. The coefficients are higher 

 in saponin than in hypotonic sea water and also vary considerably 

 from one form to another. This is not the case with erythrocytes. 

 However the action of acids upon various infusoria, as upon 

 erythrocytes, is markedly altered by change in temperature. 



A few experiments were made using chloroform, ether and 

 acetone made up in sea water (in vols. per cent., chloroform o.i- 

 0.2, and 0.37 per cent.; ether 2-6 per cent., acetone 10 per cent.). 

 The gill cilia showed the same order of resistance in these reagents 

 as in hypotonic sea water. The larval cilia were more irregular, 

 as the following list shows, though the order is not very different 

 from that obtaining in saponin. 



CHLOROFORM. ETHER. ACETONE. 



Echinarachnius p. Echinarachnius g. & p. Echinarachnius 



g. Arbacia i, 3 d. Arbacia 2, 3 



Arbacia i d. *Cumingia I 



*Asterias 3-4 Asterias 3, 6-10 d. *Asterias 2-6, 10 



2 Chcetopterus *Cumingia 



Arenicola 2 Nereis I, 2 Chatopterus 



Nereis 2 *Arenicola *Arenicola 



Cumingia Asterias i, 2 Asterias 



Asterias 6-10 



With erythrocytes Rywosch found in each of these reagents a 

 quite different order, more irregular than was observed in the 

 present experiments. 



An adequate explanation of these results is impossible at 

 present. Although detailed analyses of corpuscles have long 

 been available, there are analyses of only two of the organisms 

 used in the present experiments, made upon the eggs (not larvae) 

 of Arbacia and Asterias by Matthews. He found the Arbacia 

 egg rich in cholesterol as compared with lecithin and the Asterias 

 egg the reverse. If these lipoids alone determined resistance to 

 saponin and to hypotonic NaCl, Arbacia should be more re- 

 sistant than Asterias, but this is not the case. This may be 

 due to a change in the cholesterol content as the egg develops into 

 a larva. Certainly differences due to age occur in most of the 

 forms, especially at times of great morphological change. How- 



