214 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



ated. Thus Peas and Haricots which had been in the 

 watery solution for 4 days were skinned and the naked 

 seeds placed in fresh water which was changed daily. 

 After 14 days of such soaking, on testing with ammonium 

 sulphide the seeds went still distinctly black. It is in fact 

 practically almost impossible to wash away the HgCl 2 

 from seeds once soaked in its watery solution, any excess 

 of the salt instead of being dissolved out for the most 

 part simply soaking further in and finally permeating the 

 entire seed. On examining microscopically thin sections 

 of such seeds, treated with ammonium sulphide after 

 soaking in water the entire integuments and the cell and 

 walls of the tissue of the seed appear quite colourless, 

 whilst the protoplasm is turned dark brown. The HgCl 2 

 has therefore been dissolved by the water out of the dead 

 cell walls and integument but has been retained by the 

 protoplasm with which it has entered into combination. 

 That such a combination takes place is rendered probable 

 by the fact that Peas placed in a few times their own 

 bulk of a strong solution of mercuric chloride absorb the 

 salt in greater relative proportion than the water and 

 may so weaken the solution as to leave in it a mere trace 

 of the dissolved salt. 



Mercury has a distinct affinity for Ammonia and Amides, 

 readily forming compounds with these substances. If we 

 suppose with Loew and Bokorny that living protoplasm 

 is composed of an amide and an aldehyde group of mole- 

 cules, then the fatal action of a mercury salt upon living 

 protoplasm will be due to its combining with the amide 

 group and thus fixing the molecular arrangement in a stable 

 grouping, i.e., killing the protoplasm. It is owing to this 

 property that mercuric chloride derives its extremely 

 poisonous character. The aqueous solution or in the 

 case of certain oily seeds the alcoholic solution rapidly 



