1922] ATWOOD—FORMALDEHY DE 259 
This would seem to support the view that the injury is due more to 
exterior members retaining the formaldehyde which had been vola- 
tilized in part, than to a permanent injury to the embryo having 
resulted from the treatment. 
General considerations 
The treatment of seeds with fungicides is a process wherein one 
plant tissue (that of the parasite) must be destroyed, while another 
tissue (that of the seed) must be conserved. It is entirely probable 
that the points of fungicidal effectiveness and of danger to seeds are 
not far separated. Dr ZEEuw (26), in noting this point, quotes 
work in which it was found that the seeds were more sensitive to 
formaldehyde than spores of either bacteria or fungi, when its 
action was deeper than the surface, as is essential to secure sterile 
seeds. He believes that the high concentrations of disinfectants 
required to care for the destruction of bacterial spores is explained 
by the protection afforded by the seed coat on which the spores 
are lodged. There is an interesting similarity between this state- 
ment and the findings of Retmer (46), who observed that in the 
control of the bacillus producing fire blight of pears, a disinfectant 
which is serviceable upon tools is ineffective when used upon the 
organic substrate of the wood of the tree itself. 
It would seem that we have been too ready to jump to conclu- 
sions and give “‘recommendations”’ as to treatment upon the basis 
of germination data of more or less extent. In the light of the 
preceding results, it seems doubtful whether it is safe to postulate 
the boundary lines of safe and dangerous concentrations merely 
upon the basis of germination data. STEPHENS (50) has emphasized 
the relationship of seed treatment to subsequent lowered vitality of 
seedlings. It is thus entirely possible that concentrations which do 
not materially injure germination percentages do materially disturb 
the physiological processes related to germination and subsequent 
growth. Common agricultural practice and the findings of the 
War Emergency Board of American plant pathologists seem to 
indicate that 1-320 is at the edge of the danger zone, if indeed such 
zone is not here passed. If, as Miss Hurp (33) believes, a polymer 
of formaldehyde is deposited on dried treated wheat, and subse- 
