36 
What substances then can be used as nutrients, can 
contribute to the multiplications of cells, 7. e, for the 
formation of more protoplasm, of albuminous matter ? 
As albuminous matter contains carbon, hydrogen, nitro- 
gen, sulfur and oxygen’, we have to consider princi- 
pally the questions: Which substances are suitable 
sources for the carbon, which for the nitrogen, which 
for the sulfur? Numerous experiments made by 
Nadgeli and myself lead to the following conclusions: 
1. As sources of carbon can be used in neutral or 
weakly alkaline solutions; alcohols, phenols, organic 
acids, ketones, aldehydes, carbohydrates, ethers and 
esters, many alkaloids. 
2. As sources of nitrogen can serve: Ammonia 
salts, nitrils, amido acids, amins, ureas, guanidins, alka- 
loids, nitrates and nitrites. ; 
. As sources of sulfur can serve: Sulfates, sul- 
fites, hyposulfites, sulfo acids, mercaptans, sulfons. 
Now of all these substances, so very different in 
chemical structure and character, the bacteria can form 
synthetically the same albuminous matter, the substance 
of their own protoplasm. There can be no doubt that 
in all these different cases the same proteids result, 
otherwise the structure and functions of the kind of bac- 
terium grown in these solutions would change, and 
new species would be formed with ease, according to the 
difference in food. Now, if we want to get an insight 
into this remarkable process, we must at first consider 
which substances are the fittest sources of carbon, which 
are neither useful nor poisonous, and which are directly 
noxious ? 
in regard to the first question we must draw from 
numerous observations the following conclusions for 
most of the non-pathogenic forms of microbes: 
1. Hydroxylated acids are better than the corres- 
ponding non-hydroxylated ones, e. g., lactic acid, 
C, H,, O,, is better than propionic acid, C, H, O,. 
2. Polyvalent alcohols are more favorable for the 
development than the corresponding monovalent ones; 
for instance, C, H, O,, glycerin, is better than propylic 
alcohol, C, H, O. 
3. The nutritive quality of the fatty acids and monova- 
lent alcohols decreases with the increase of the number 
of carbon atoms in the molecules; for instance, acetic 
acid, C, H,O,, is better than butyric acid, C, H, O, ; 
methylic alcohol, CH, OH, is better than amylic alco- 
nol, Cle, Olel 
4. The entrance of aldehyd or keton groups in- 
creases the nutritive qualities: glucose, C; H,,O,¢, is 
better than mannite, C; H,, O, ; acetyl acetic ester is bet- 
ter than acotic ester (in 0.1 per cent solutions). 
5. Neither noxious nor nutritive properties have 
been observed by me with picronitric acid, chloralhy- 
drate, pinakon, ethylendiamin, glyoxal, amidoacetal; 
very poor nutrients are acetoxim, diacetonamin and 
maleinic acid.* (These substances were applied in neu- 
tralized solutions containing o.1-0.5 per cent). Ac- 
cording to B. Meyer also mesaconic, citraconic, para- 
methyl succinic, dimethyl succinic, and benzoyl succinic 
acid aré incapable to serve as food.* 
6. The poisonous qualities are determined by the 
energy with which the labile atom groups of the living 
protoplasm are attacked; chloroform, phenyl, hydrazin, 
formic or methylic aldehyd may be mentioned here. 
Those observations permit us to draw certain conclu- 
sions as to the group useful for synthetical purposes. 
If methylic alcohol is better than amylic alcohol, then ~ 
the group serving for synthetical purposes will be, of 
1We leave here the nucleins out of consideration, they contain phosphoric 
acid in their molecule. 
2 he isomeric fumaric acid is, however, a good nutrient. 
$I may add that methylamin is a better source of carbon than trimethyla- 
min, 
SCIENCE Y AASTI 
72 
course, more easily prepared from the former; thesame is 
true for acetic acid compared with butyric acid: we are 
forced to the conclusion that the group for commencing 
the synthesis of albuminous matter is a very simple one, 
with only one atom of carbon, and as methylic alcohol 
as a saturated compound cannot be used as such, the 
group in question can only be methylic or formic alde- 
hyd. Neither can acetic acid be used as such; it must 
be converted into a substance suitable for condensating 
processes, and this cannot be anything else than formic 
aldehyd also in this case. If this conclusion be correct, 
then we understand why substances containing the 
group CH OH are very favorable for nutriment and in- 
crease in their useful qualities with the number of these 
groups (the polyvalent alcohols, the polyvalent acids). 
We understand also why such substances are capable to 
nourish certain bacteria endowed with fermentative 
properties, even in absence of air, while substances with- 
out this group can be used as food only in presence of 
air, oxydation being then necessary to form this group. 
But how is that conclusion possible, if formic aldehyd 
is a poison? No doubt this seems an objection of 
weight; but if we consider how easily the formic alde- 
hyd is changed under condensating influences, and how 
indifferent simple combinations of this aldehyd are, the 
objection appears no longer so serious; we must only 
adopt the view that the formic aldehyd undergoes rapid 
transformations, and that no molecule formed remains 
unchanged for a second. 
If certain substances, as picronitric acid, chloralhy- 
drate, pinakon, cannot be used as nutrients, we may 
find the reason in this, that those substances offer too 
much resistance to the bacteria for the production of 
formic aldehyd; hence no albuminous matter can be 
synthetically prepared, the living protoplasm cannot 
grow, not increase, the formation of new cells becomes 
impossible. It is also simply explained, why oxalic 
acid cannot be used as food; it can neither by oxydation 
nor by splitting yield formic aldehyd. Neither are the 
salts of formic acid suitable nutrients, the conversion 
into formic aldehyd being rather difficult. I have ob- 
served only one kind of bacterium that is able to grow in 
diluted (0.5 per cent) solutions of sodium formiate; it 
occurs in the dust of air and forms reddish pellicles.* 
The conversion of formic acid into formic aldehyd by 
this microbe might be explained by the following equa- 
tions: 
H-CO OH | CHO 
— i ae Jat, ©) 
H-CO OH § CO OH 
2 Mol. Gpmeacia) Seat acid 
CHO 
l = CHLO 4 Heo 
CO OH 
(SSS \ 
Formic aldehyd. 
4Centralblatt f. Bacteriologie, 1892, XII., No. rq. 
(Zo be continued.) 
—The December election of officers of the Wil- 
son Ornithological Chapter of the Agassiz Asso- 
ciation resulted as follows: President, Willard N. 
Clute, Binghamton, N. Y.; Vice-President, Reuben M. 
Strong, Oberlin, O.; Secretary, William B. Caulk, Terre 
Haute, Ind.; Treasurer, Lynds Jones, Oberlin, O. The 
chapter is in a very flourishing, condition, with seventy- 
three active, four honorary and thirty-one associate 
members. ‘The past year has been devoted to a special 
study of the Warblers, and the forthcoming report prom- 
ises to make a very interesting paper. Any informa- 
tion regarding the chapter will be cheerfully furnished 
by the secretary, 
