2I 4 



C. M. CHILD AND L. H. HYMAN. 



TABLE. 



dyes showed some difference in degree of toxicity. The plus or 

 minus sign following the figures denoting times indicates that 

 the exact time was not observed. The data for neutral red are 

 not tabulated because the gradual precipitation of the dye in 

 aqueous solution makes it impossible to maintain a constant con- 

 centration, but in a concentration originally approximately 

 0.005 per cent, of the sample used disintegration began after 1-2 

 hours and was completed after 6-7 hours. 



Young, recently separated animals disintegrate in half to two 

 thirds the times given in the table, animals regenerated from 

 pieces resemble the young animals in susceptibility, and in starved 

 animals the ectoderm is more susceptible than in well-fed animals 

 while the entoderm, being in large measure functionally inactive, 

 is usually less susceptible than in well fed animals. 



In general the susceptibility of H. viridissima and H. vulgaris 

 to a given concentration of a particular agent is somewhat greater 

 than that of H. oligactis, but the low susceptibility of H. viri- 

 dissima to alcohol (p. 207) is apparently an exception to this rule. 



