284 Frederick Stoivard : 



The results are, as regards the comparative non-diffusibility 

 of the dissolved substances through the skin or rind of the 

 tuber, quite comparable with those derived from otherwise 

 parallel experiments . save that NaCl or H0SO4 was displaced 

 by boracic acid. 



It may be definitely stated that boracic acid like NaCl and 

 H2SO4 in acpieous solution, under the conditions of experiment 

 indicated, does not diffuse through the skin of the tuber. 



The usual planting, storage and cooking tests were carried 

 out with this material ; no signs of growth were apparent^ 

 even after a lapse of two months, thus show^ing that the treat- 

 ment had effectively extinguished any residual vitality the 

 buds of the treated tubers may have possessed prior to the insti- 

 tution of the planting tests. The storage and cooking tests 

 were quite satisfactory, the treated tubers retaining their 

 normal solidity, cooking well, and being quite w^holesome. 



A small parcel of tubers immersed in a 2 per cent, boracic 

 acid solution, contained in tins which jDrior to shipment were 

 hermetically sealed, were sent from Melbourne to Perth. These 

 arrived in good order, little or no bacterial activity w^as evident 

 in the solutions, and the tubers on opening the tins were found 

 to be quite sound and solid. After exposure, however, parts 

 of the surface of each tuber became much discoloured, and in 

 these superficial areas bacterial decay set in and rapidly pro- 

 gressed. 



It is highly probable that during transit the tubers were 

 unavoidably bruised at the parts of their surfaces at which, 

 after removal from the solution, discoloration and eventually 

 decay of the subjacent tissue took place. As possible injury by 

 bruising during the laboratory operations was both controllable 

 and avoidable, the tubers in my experiments did not exhibit 

 these degenerative changes. 



It is interesting to note that in these experiments with boracic 

 acid as the steep-medium little or no bacterial development 

 was apparent. 



The results afforded by the foregoing experimental data 

 justify the following conclusions: — 



(1) When mature blight-free tubers are steeped in aqueous 

 solutions of either common salt, sulphuric oi- boracic acid, under 



