New York AGricuLttuRAL ExperRIMEentT STATION. 521 
subject of systematic investigation until the work by the writer 
at this Station showed that self-sterility, either absolute or to a con- 
siderable degree, is found with a large number of cultivated Ameri- 
can grapes. 
METHODS OF INVESTIGATIONS. 
THE VINES. 
The vines which have been used in these investigations have 
been generally thrifty, vigorous and in a normally productive 
condition. 
The Station vineyards, in which most of the work has been 
done, are on a fertile clay loam which favors a strong growth of 
vine. Some weak kinds, like Rebecca, have not made a good 
erowth, but most of the varieties are probably stronger growers 
here than they are on the average on land better suited for vine- 
yard purposes and especially for developing high flavor in the 
grape. 
| Although the vines in these vineyards generally make good 
growth, they are seldom too vigorous to yield well. Some idea of 
the yield that may be expected from productive varieties on this 
soll may be gained from the following statement of the annual 
yield per vine of Worden in a Station vineyard. 
Six Worden vines planted in the fall of 1892 yielded their first 
fruit in 1895, averaging about half a pound per vine. In 1896, 
the fourth season after planting, the yield was 11.63 pounds; in 
1897, 23.38 pounds; and in 1898, 18.31 pounds per vine. 
COVERING THE CLUSTERS. 
In testing a variety for self-sterility the clusters which have 
been selected for the test are covered with paper bags before the 
blossoms open. This excludes outside pollen so that if pollina- 
tion takes place the pistil must either receive pollen from its own 
blossom or from some other blossom in the same cluster. Ordinary 
manila paper bags obtained from the grocer have been used, the 
