230 Alfred J. Eu-(irt : 



Solutions of potassium cliloi-ate showed no signs of any poisonous 

 action up to strengths in wiiicli a strong osmotic action Avas exer- 

 cised. Tlius even after five days at 130 C. in a 5 per cent, solution, 

 and in spite of the fact that the prepared spots were slightly de- 

 pressed owing to the withdrawal of water, no signs of any poison- 

 intr action could be seen beyond a faint superficial browning on 

 some, but not all, of the prepared spots. 



To test the effect of an acid, sulphuric acid was selected; pre- 

 pared potatoes immersed in it, and examined after one day in the- 



SULPHURIC ACID, EXPOSUEE FIVE DAYS, TEMPERATURE 

 AVERAGING 12-13°C. 

 1 per 250. 1 per 1000. 1 per 10,000. 1 per 50,000. 1 per 200,000. 



Dead tissue 8-10 - Dead tissue 5-6 - Pits 2 mm. - Faint super- - No signs of 

 mm. beneath mm. deep, deep, faint ficial brown- poisoning, 



each prepared quite white. brown. ing. 



spot, but quite 

 white. 



Sulphuric acid is feebly acid to litmus paper up to 1 c.c. in 

 100,000 of water, but shows no perceptible acidity with 1 in 

 1,000,000. Hence litmus is slightly more sensitive to acid than 

 potatoes are. Using potatoes with small sprouts, the latter were 

 completely destroyed and rotted in concentrations up to 1 in 

 10,000, with 1 in 50,000 the tips, of the sprouts were slightly 

 affected, but a 1 per 200,000 solution did not produce any more 

 effect than immersal in distilled water. 



Using caustic potash, prepared snowflake potatoes were im- 

 mersed for five days at an average temperature of 13o C. in | litre 

 of solution, then cut open along the line of prepared spots, and 

 examined after 2 hours' exposure to air. 



CAUSTIC POTASH. 



1 gram per 100 c.c. water. Pits 3-4 mm. dep. 



1 gram per 500 c.c. water. Pits 1-2 mm. dep. 



1 gram per 1000 c.c. water. Pits siiperficial to 1 mm. deep. 



1 gram per 2000 c.c. water. Faint, superficial browning only. 



1 gram per 5000 c.c. water. No distinct signs of poisoning. 

 Snowflake potatoes appeared to be comparatively in.sensitive to 

 antesthetics. 'J'hus with an immersal of 3 days at 13-1-10 c. in 

 a 5 pel- cent, solution of ether, the tissue was killed to a depth 

 of 3-4 mm. beneath the prepared spots, but only browned on 

 exposui-e to air, presumably owing to the ethei- i-etarding oxidase 

 action. With a 1 per cent, solution the tissue was killed on the 

 surface, and hardly browned at all, while no signs of poisoning 

 were shown with a 0.2 per cent, solution. 



