1899] TOXIC EFFECT OF DELETERIOUS AGENTS 383 
ionic H. Bokorny (’88) found that ammonia in os concentra- 
tion, in common with other basic substances, caused the produc- 
tion of granules in the protoplasm of Spirogyra cells, but failed 
to modify otherwise the normal activities of the cell. Detmoor 
(94) found that a 10 per cent. solution of ammonia at first 
energetically excited the protoplasm of Tradescantia hairs, later 
producing anzsthesia. Washing with water, however, restored 
the original characters of the protoplasm. From these data it 
would seem that hydroxids are more fatal to the molds than to 
the higher plants. 
Formaldehyde, HCHO; 0.553, 7.43, 2. Formaldehyde, as 
Was anticipated, proved to be one of the most deadly agents 
tested, being surpassed in this respect by mercury, silver, and 
the two chromates only. Chemically considered, formaldehyde — 
isa very unstable compound intermediate between methyl alco- 
hol and formic acid, being in fact the intermediate step in the 
oxidation process by means of which the latter is derived from 
the former. It is both a reducing and oxidizing agent, ‘and this. 
together with its great instability may account for its extremely 
‘oxic properties toward fungi. 
To many kinds of protoplasm, including that of the higher 
animals and perhaps the higher plants, formaldehyde is non- 
toxic. Instances are on record of persons having drunk a I per 
cent. solution without inconvenience (Arthur ’97, p. 21). To 
the lower animals, however, it is more toxic, > being fatal to 
Yorms, mollusks and isopods in two hours (Loew ’88). Acton 
89), in experiments on the assimilation of organic compounds 
by Steen plants, found that while they could use glucose, sac- 
charin, glycerin, etc., they failed to use aldehydes or their 
detivatives. Cohn (’94) found a I per cent. solution very fatal 
0 Spirogyra. 
For the fungi, however, there is no doubt that in formalde- 
Yde we have one of our safest, most energetic, and most ser- 
: "iceable poisons, —— proved fatal to Aspergillus and Penicillium, 
3 512 
