Physarum variabile Rex. 
Physarum viride Pers. 
Spumaria alba DC. 
Stemonitis ferruginea Ehreub. 
Stemonitis fusca Roth. 
Stemonitis splendens Rost. 
Trichia afinis De Bary. 
Trichia favoginea Pers. 
Trichia persimilis Karst. 
Tubulina fragiformis Pers. 
ACRASIEAE, 
Chondromyces lichenicolus Thaxter. 
Myxococcus stipitatus Thaxter. 
Myzxococcus rubescens Thaxter. 
THE GERM OF PEAR Buicutr. By LILLIAN SNYDER. 
It is certainly an established fact that the well-known disease of Pear 
Blight, which causes such devastation among our pear, apple and quince 
trees, is caused by bacteria within the growing tissue of the tree. The 
germ which causes the disease was discovered by T. J. Burrell, and was 
first described and named by him in 1882.* 
The germ I have isolated from the pear tree, and which I think I 
can say without a doubt causes the disease of the tree, I shall designate 
by the name used by other writers, and originated by Prof. Burrell; that 
is, Micrococcus amylovorus. Whether the above germ spoken of is the 
same as the one handled and studied by Prof. Burrell, and also by J. C. 
Arthur,+ I leave to be gathered from the results of my experiments. 
Early in March, 1897, I attempted to separate the germ which causes the 
blight of the tree. Various methods were used, such as cutting pieces of 
diseased bark of pear, with a sterilized knife, and placing in bouillon; 
also by inserting a platinum needle between the bark and wood of dis- 
eased tissue and streaking upon agar. The latter proved the most success- 
* Eleventh Report of the Illinois Industrial University, p. 42. 
+ Proceedings of the Philadelphia Academy of Nat. Sciences, 1886, pp. 322-341. 
