THE PROTEIN CONTENT AND MICROCHEMICAL TESTS 
OF THE SEEDS OF SOME COMMON IOWA WEEDS. 
L. H. PAMMEL AND ARTHUR W. DOX. 
Weed seeds are recognized as an important factor in the 
dietary of our useful birds. Other things being equal, those 
seeds haying the highest nutritive value might be expected to 
figure more prominently in this regard than seeds less nutritious. 
In animal feeding, the protein content of the feed is taken as the 
measure of its nutritive value, and the cost of the feed is de- 
termined largely by the protein content as ascertained in the 
chemical laboratory. Hence the protein content of weed- seeds is 
of some economical importance as related both to the maintenance 
of our native birds and to the control of the weeds themselves. 
The list of species, the analyses of the seeds of which are here 
reported, comprise but a small part of the weed flora of the 
state. It is hoped, however, that the writers may have oppor- 
tunity to extend the list during the coming season. The seed 
samples were collected in the vicinity of the Iowa State College 
during the late summer and early fall of 1916. All chaff, hulls, 
appendages, etc., were removed by rubbing in a cloth, screening, 
and winnowing, until the seeds were practically clean. The 
samples thus obtained were spread out on watch glasses in a 
dust-proof cupboard for several weeks until they Avere air-dry. 
The determinations here recorded are all on the air-dry basis. 
As a matter of additional interest the weight of fifty seeds was 
determined in each case, and from this value the approximate 
number of seeds per gram was computed. Nitrogen was de- 
termined by the well known Kjeldahl-Gunning method and the 
value thus obtained was multiplied by the factor 6.25 to convert 
it into protein. 
For the purpose of ascertaining the microscopic characters of 
the weed seed investigation made chemically by Doctor Dox, a 
micro-chemical test also was made to determine the presence of 
starch, protein and fat. Microscopic tests have been made of the 
seeds of a great many weeds. A brief reference to some of the 
papers will not be amiss in this connection. One of us made a 
study of the anatomical characters of the seeds of Leguminosse, 
