~ BRIEFER ARTICLES. 
od 
Germinating seeds in sawdust.—Germinating seeds in sawdust is 
not so commonly practiced, we believe, as it might be, owing to the 
fact that sawdust frequently has a detrimental effect on root growth. 
In our intercourse with other teachers of botany we have often been 
reminded of this fact; andin many instances we have observed the 
roots of germinating plants grown in this medium to be in a very un- 
healthy condition. 
For the benefit of those who use sawdust in germinating seeds, and 
have experienced difficulty in obtaining satisfactory results, we offer 
the following suggestions. 
The difficulty lies in the selection of the sawdust. Care should be 
taken to select sawdust which contains no tannin, as this is the ele- 
ment which causes abnormal root growth. Roots grown in. sawdust 
containing tannin show a reddish coloration, are crooked, and are 
very much reduced in size. In testing a number of different kinds of 
sawdust, we have found that that taken from the varieties of oak and 
chestnut should be avoided, since these woods contain tannin in suf- 
ficient quantities to cause the tannin poison. On the other hand, 
sawdust obtained from the conifers has no detrimental effect what- 
Soever to root growth. ph 
The sawdust taken from hemlock, which is noted for containing 
large quantities of tannin in its bark, did not cause the tannin poison; 
neither did a water solution of the sawdust give a tannin reaction 
when tested with a solution of molybdate of ammonia in concentrated 
ammonium chloride. This is due to the fact that the tannin is located 
In the bark in this species and our sawdust was from heart-wood. 
That the abnormal appearance of roots grown in chestnut or oak saw- 
dust is caused by tannin can be readily shown by saturating any Saw- 
dust suitable for normal growth with a 1 per cent. solution of tannin. 
one has an unknown variety, or a mixed sawdust in which the ele- 
ments are not readily recognized, a water decoction can be prepared 
and a portion of the same tested for tannin by one or more of the well 
known tannin tests. 
In our opinion, no germinating medium is better than sawdust, as 
Clean straight roots for class study or for experimental purposes can 
be readily obtained. We have never experienced difficulty with any 
Sawdust which failed to give the tannin reaction, and during the past 
Year we have used the same sawdust continually without changing: 
