Action of Chemicals on Fotato-Tuhers. 275 



It is probable that extraction of certain proteins and their 

 derivatives occurs more rapidly with a 5 per cent, brine than 

 with the higher concentrations, although the possible inhibitive 

 effect of these higher concentrations on bacterial activity is not 

 excluded. The point is one for future investigation, and re- 

 quires controlling by Kjeldahl nitrogen estimations, and the 

 institution of •' salting out " experiments. The fact remains 

 that toAvard the third to sixth day the steep-solution becomes 

 a veritable culture medium. 



These suggestions regarding the manner in which brine func- 

 tions are supported by the fact that in parallel experiments 

 in which like material was steeped in plain water, bacterial 

 development was not so advanced, as shown by both micro- 

 scopical and macroscopical observation. 



Blight-free Unpeeled Tubers. 



The experimental results so far related indicate that when 

 peeled tubers are steeped in brine solutions, salt penetrates 

 rapidly and freely into the tissue, and plasmolysis and ulti- 

 mately death of the cellular units take place. 



It remained to endeavour to ascertain whether entry of salt 

 takes place so freely when intact, unpeeled tubers are steeped 

 in brine solutions. 



In the table hereunder and those which follow, the sum- 

 marised experimental data are typical of and selected from a 

 mass of similar essays, in which three different types of tubers— 



(1) mature thick-skinned Victorian tubers, 



(2) less mature thin-skinned Victorian tubers, 



(3) less mature thin-skinned Victorian tubers, 

 served as the experimental material. 



At the outset it may be stated that non-removal of the skin 

 of the tuber prior to steeping, eft'ectively retards the entry of 

 the solute. This fact is well shown by the results of the follow- 

 ing typical experiment. 



Experiment : — Two lots (5 each) mature thick-skinned Vic- 

 torian tubers, steeped in brines (a) and (b) for ten days. First 

 determinations of chloride content of brines made after three 

 days' steeping and subsequently after 4, 8 and 10 days. 



