INJUEY AND RECOVERY 89 



experiments. Under these circumstances the net resist- 

 ance at 18° C. did not vary much from 1070 ohms. For 

 example, in a series of determinations of 10 different lots 

 of tissue, the highest reading was 1090 ohms, and the 

 lowest 1055 ohms. These lots of tissue were allowed to 

 remain in the laboratory under different conditions. 

 Some were in running salt water, some in quiet salt water 

 in pans of various sizes, a part being placed in direct 

 sunlight (where the temperature rose to an injurious 

 point) while others were kept in a cool place, in partial 

 shade. At the end of 24 hours, there was no difference 

 in the appearance of these lots, but their net electrical 

 resistance varied from 200 ohms to 1090 ohms. All were 

 then placed side by side in the same dish. Those with 

 the lowest resistance were the first to die. The others 

 died in the order indicated by their electrical resistance. 



Determinations of the resistance made it evident that 

 in no case did visible signs of death make their appear- 

 ance until twenty-four hours after death occurred, and 

 subsequent experiments showed that in some cases (espe- 

 cially at low temperatures and in the presence of certain 

 reagents) they may not appear until several days 

 after death. 



It was found that material from one locality showed 

 a low resistance, and subsequent examination showed 

 that it was contaminated by fresh-water sewage. The 

 appearance of the plants was not such as to lead to their 

 rejection for experimental purposes. They did not sur- 

 vive as long in the laboratory as plants of normal resist- 

 ance taken from the other localities. 



It may be taken for granted that vitality, whatever 

 else it may signify, means ability to resist unfavorable 

 influences. When organisms which are of the same kind, 



