Apr. is, 1921 
Susceptibility of Injured Seeds to Molds 
107 
which attacks them in the blotters. Rhizopus rarely attacks seeds which 
have been treated with copper sulphate, even if the seed coat is broken 
over the endosperm. 
The susceptibility to Penicillium of seeds injured by copper sulphate 
is shown as strikingly in barley as in wheat. The seeds uninjured by the 
chemical escape attack unless, of course, the testa is broken over the 
endosperm. 
Seed stored without drying after treatment with a 1 to 320 formalde¬ 
hyde solution is much more resistant to the attack of molds than is un¬ 
treated seed similarly stored. This is shown by the following experiment. 
Samples of barley and wheat were treated in the usual way by a 
10-minute dip followed by a drain of 10 minutes. The excess moisture 
was removed and the seeds were dusted with Penicillium spores, as were 
also control lots treated in a like manner with water. All were sealed in 
small screw-top bottles. As was shown recently in another paper (13), 
this formaldehyde treatment does not injure the seeds so long as they are 
not allowed to dry with consequent formation of paraformaldehyde. 
After one month, samples of each lot were germinated, with the results 
shown in Table III. 
Table III .—Germination of wheat and barley soaked in formaldehyde solution and in 
water, followed by dusting with Penicillium spores 
Sample No. 
Barley. 
Wheat. 
1 to 320 
formalde¬ 
hyde. 
Water. 
1 to 320 
formalde¬ 
hyde. 
Water. 
Per cent. 
88 
90 
Per cent. 
72 
76 
Per cent. 
62 
84 
Per cent. 
32 
56 
Copper sulphate has an even stronger inhibiting effect than formalde¬ 
hyde on the development of molds on wheat in damp storage. In our 
experiments, however, Penicillium developed slowly in such seed, while 
it more rarely appeared in the seed stored similarly after formaldehyde 
treatment. Inhibition of Penicillium by the latter apparently gave 
opportunity for Aspergillus to develop. Aspergillus appears to develop 
most conspicuously when unfavorable factors to which Penicillium is 
more sensitive prevent the development of the latter. As a result, 
stored seed treated with copper sulphate has been destroyed largely by 
Penicillium and the formaldehyde-treated seed by Aspergillus, although 
both lots were stored under identical conditions. 
The seed used in these experiments, one of which is summarized in 
Table IV, was machine-thrashed Little Club wheat in good condition, 
about 30 per cent of the grains having the seed coats broken over the 
embryo but with practically no endosperm injury. The varying degrees 
