Physiology of Regeneration 635 
TABLE XxX 
| 
SEPTEMBER 5 TO SEPTEMBER 15 (1908), NUMBER OF SEGMENTS 
Sea-water—8o parts te 16 18 19| 14] 17) 19| 16] 18) 14] 17| 18] 18] 19) 16) 17] 19| 20 
Dist. water—2o parts New la |'3:|3 Aan eANl An leanianlr4s eau ie cele ai en Ralasileik 
| Cede ales ad eel 
TABLE XXXI 
| | a 
SEPTEMBER 5 TO SEPTEMBER I5 (1908) | NUMBER OF SEGMENTS 
Sea-water—go parts Old | 16 | 17 | 19 | 17 | 19 | 18 | 18 | 16 | 18 | 20| 16 | 18 
Dist. water—io parts Wew,|/ 3" ||" 3 | Bisley Sic lle oe eee ear lees Sele’ | om a eee 
The same results were also obtained from other experiments. 
In these, too, there was no good evidence of a beneficial or a 
detrimental influence. 
The concentration of sea-water above the normal was accom- 
plished by adding various quantities of a gram-molecular solution 
of MgCl, and KCl. As regards the last substance, it may be 
stated that, even in quite small amounts, it proved absolutely 
fatal to the animals, and they died very rapidly. Ofthe molecular 
solution of MgCl, various quantities, from 1.25 cc., to 15 cc. were 
used, and to these enough sea-water was added to make Ico cc. 
When as many as 15 cc. of this solution are added to the sea- 
water (85 cc.), there is no trace of regeneration, even at the end 
of ten days after the operation, the worms dying out in great 
numbers. In a mixture containing 10 cc. of the solution a few 
of the worms regenerated even as many as three segments, while 
other worms did not regenerate at all or died. ‘The use of 5 cc. 
of the MgCl, solution does not in any way hinder the normal 
process of regeneration, even as many as 5 segments being regen- 
erated. Although there is no advantage of which one could be 
certain in favor of worms regenerating in sea-water of this con- 
centration, there is also no apparent disadvantage. When, how- 
ever, smaller quantities of MgCl, are employed, there frequently 
occurs an acceleration of the rate of regeneration, which will be 
more or less pronounced in different experiments. In Tables’ 
