THE PHYSIOLOGY OF REGENERATION 335 



more closely that which was established for the control, i.e., 

 73.8 per cent. I do not wish to emphasize these conclusions too 

 strongly at this point, for a survey of the results of the remaining 

 experiments will lend more weight to them. The data can be best 

 appreciated, however, when expressed graphically. Fig 5 con- 

 tains curves based upon the quantitative determinations recorded 

 in table 1. The horizontal Hne is divided into equal spaces, each 

 of which represents a period of one day ; upon the ordinates are 

 indicated at the left weights in milligrams, at the right percent- 

 age of water. The curves show: (1), by a continuous line, the per 

 cent of water; (2), by a dot-and-dash line, the average weight of 

 a live worm; (3), by dashes, that of dry substance, and (4), by 

 dotted line, that of water as determined experimentally for the 

 indicated days. The percentage curve shows for water a rapid 

 rise followed by an abrupt fall ; this in turn is followed by a more 

 or less slow decline. It will also be noticed that the period of 

 maximum water content falls within the first fourteen days after 

 operation. The curve bears a general resemblance to similar 

 curves for growing animals. 



The other three curves, namely those of the total weight of a 

 worm, of its dry substance and of its water content, all tend down- 

 wards. The quantity of dry substance is progressively decreasing, 

 rapidly at first and much slower subsequently. But examining 

 the dotted-line curve, representing the absolute quantity of water 

 in the regenerating worms, it will be observed that, while declining 

 more or less rapidly at the very beginning and during the latter 

 two-thirds of the experimental period, it remains practically at 

 a constant level for some ten days. It should also be observed that 

 the total body weight for the same period is scarcely changed. 

 These facts are especially interesting when correlated with other 

 phenomena characteristic of this period, namely, the greatest 

 intensity of the regenerative process and the highest per cent of 

 water in th he regenerating organism. The last phenomenon is 

 therefore, the resultant of two factors: first, the lossof dry sub- 

 stance ; secondly, the retention of water in the organism. Beyond 

 this period the curve of the absolute quantity of water falls off 

 quite rapidly, in fact, more so than the curve showing the quantity 



