BORTHWICK AND WILSON—Two Rust DISEASES OF SPRUCE. 69 
which are in a backward condition when the sporidia are ripe 
are not infected, while at the same time others may have passed 
the susceptible stage and thus escape the disease. 
As a result of the attack the infected leaves die and fall 
from the tree, and thus a considerable defoliation may take place. 
The disease, however, usually fails to maintain itself through a 
long series of years on any one tree and in consequence felling 
is not desirable. 
In the last issue of the Quarterly Journal of Forestry,* which 
we have just received on going to press, Dr. Somerville states 
that on April 21st specimens of spruce branches badly attacked 
by Chrysomyxa abietis were sent to him by Mr. Neil MacGregor, 
Bridge of Dye, Banchory, Kincardineshire. The specimens _ 
were from trees about twenty years old which were planted 
under old larch and Scots pine, and were situated about seven 
miles from the nearest part of the Durris Woods, in which Dr. 
Somerville discovered the disease in IgII. 
We desire to thank Professor Trail and Mr. P. Leslie, M.A., 
B.Sc., who have kindly supplied information as to the distribution 
of Chrysomyxa abtetis. 
* Quart. Journ. Forestry, ix (1915), 253. 
