FORMIC ALDEHYDE. 



317 



exclusively to disinfect seed for sowing, it is especially from this point 

 of view that it has been examined. Its vapours have almost the same 

 action as its dilute solutions. The action of 0-1-0-2 per cent solu- 

 tions of formic aldehyde (0'25-0"5 of formaline) is hurtful both to 

 cereal grains and leguminous seeds, for it retards germination (Kruger, 

 Arieti, Niger). However, beet seeds suffer less. F. Bruning has 

 examined the point, and got the following results with oats : — 



TABLE LXIV. — Showing Effect of Steeinng Seed-Oats in Forniol Solutiona 

 on Germination. 



A, seeds sown undried ; B, seed air-dried for twenty-four hours before 

 sowing. These results show that a 0'3 per cent solution of formic alde- 

 hyde ( = 0"75 per cent of formol) does not act on the germinative faculty 

 but solely on the germinative capacity ; it therefore only retards germi- 

 nation without abolishing it. Cranefield has shown to what point the 

 germinative capacity is diminished by treatment with formol, and has 

 demonstrated the effect of the concentration of the formol bath (steep) 

 on the latter. 



TABLE LXV. — Sliowing Effect of Twenty Minutes' Steeping in Formol Solu- 

 tions of Various Strengths on the Germinative Capjacity of Seed-Corn. 

 Water = 94-5 Per Cent. 



Solutions of formol lower the germinative capacity of seeds the more 

 formic aldehyde they contain. The following interesting table, giving 

 the result of two series of experiments, proves that the injurious action 

 of formol does not depend on the duration of the steep. 



