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40 



were cul into fine strips and alcohol poured over them; then the portions were 

 boiled in the water-bath, which process was repeated after a few days. The por- 

 tions were put aside for at least a month before the alcoholic extract was analysed. 

 By way of making sure that the method used for extracting the amides was suffi- 

 cient, the following experiment was carried out : Two portions of potatoes were 

 boiled with alcohol as already described, the tubers of the first one having previ- 

 ously been cut into fine strips, those of the second into strips double the size of 

 those in the former. 7 days and 14 days after this process equal amounts of ex- 

 tract of each portions were analysed as for amides and the same results were 

 found, i. e. a period of 7 days was sufficient for a complete extraction of the above 

 mentioned substances both as regards the portions containing fine strips and those 

 containing coarse ones; or the last analyses would have shown higher results. The 

 results are as follows: 



After 7 days 

 9-2 mgrs N of amides 

 8-4 - - 



After 14 days 

 9"1 mgrs N of amides 

 8-3.'i - - 



At first 3 experimental series were made of which the first was to demon- 

 strate the eff"ect of ether on wounded potatoes in the last stage of the resting- 

 period; the second one was to demonstrate the effect of injury and the third one 

 was determined to show whether quite young potatoes react upon the above men- 

 tioned factors in the same manner as the older ones. 



Series I. 

 Tubers of "Magnum bonum" were reaped in autumn 1906. The experiments 

 were carried out Febr.— April. 1907. The tubers were slit longitudinally; those in 

 1. were however quartered. Temp. 10 — 11°. Jars of 14 liters' capacity were used 

 for the exposure. 



Mrgs Decrease 



iV of of N of 



amides amides 



I a. 



Directlj' cruslied 



2 days without etlier 



1 day with 0-2 c.c. ether per liter 

 (= 28c.c.). 1 day without ether 



2 days with 02 c.c. ether per liter 



(= 2-8 c.c.) 



1 day without ether , . 



1 day with 0-1 c.c. ether per liter 

 (= 1-4 c.c.) 



3 days without ether 



3 days with 0-1 c.c. ether per liter 

 (= 1-4 cc.) 



106-10 

 111-02 



106-77 



98-68 

 119-20 



118-75 

 160-07 



152-45 



mgr. 



8-50 

 7-95 



8-15 



7-80 

 13-66 



14-93 

 13-85 



13-95 



»/„ 



6-47 

 4-12 

 8-24 



r-8-91 



^0-71 



After the exposure: 

 fresh. Wounding-corli was 

 formed on the cut. 



■ I fresli : wnunding-corlc 

 I formed. 



