172 BULLETIN OF THE BUSSEY INSTITUTION. 
ence to the adjacent grass; and Braun, like Beckmann, says that it 
may be destroyed by long-continued pasturing with horses. Sprengel * 
reports that horses and sheep are fond of all sorts of Hquisetacee, and 
eat them without detriment ; whereas neat-cattle, when driven by hun- 
ger to eat them, are liable to get diarrhoea, or even finally to die. 
In opposition to the foregoing statements, and to many others of like 
import that might be cited, I find two statements to the effect that 
equisetum plants may sometimes be injurious even to horses. The bota- 
nist, Nuttall,t who observed Hquzsetum hyemale (7.e., the true scouring 
rush) growing abundantly on the banks of the Missouri River, below the 
Platte, where it was known as “ rushes,” says that it is found to be in- 
jurious to horses who feed upon it for any considerable length of time. 
On the other hand, Mr. W. H. White,t of Connecticut, is said to have 
published, in the “ New England Homestead” for 1873, an account of 
the poisoning of horses by Hquisetum arvense. Since I have no access 
to the paper in question, and have never seen a detailed account of Mr. 
White’s statement, I am unable to form any opinion as to its impor- 
tance. 
Nosemann,§ in his prize essay, ascribes the hurtful effects of the 
equisetum to its astringency ; and he dwells upon the fact that the juice 
of the plant gives a black coloration when mixed with iron-vitriol. It 
is true, as has been already stated on page 167, that the juice of the 
plant blackens the knives with which it is cut; but this blackening is 
no more pronounced than that caused by many apples and by a great 
variety of other harmless fruits and vegetables. It would seem much 
more probable that the injurious action of the equisetum plant is purely 
mechanical, and that the intestines of the animals are irtitated by its 
harsh, rough stalks and leaves. ‘The rough, silicious character of the 
outer surfaces of the various kinds of equisetum is well known. One 
species of the plant, the scouring-rush proper (Hquisetum hyemale), was 
formerly much used for polishing wood, horn, ivory, stone, and metal. 
It was imported into England from Holland, under the name of Dutch 
rushes for this purpose; and was not only used by whitesmiths, cab- 
* Erdmann’s “ Journal fiir tech. und ekonom. Chemie,” 1829, 5. 44. 
+ Cited in Gouverneur Emerson’s edition of C. W. Johnson’s “ Farmers’ and 
Planters’ Encyclopedia,” New York, 1855, p. 647. 
t As cited in “ American Agriculturist,” June, 1877, p. 9. 
§ Beckmann’s “ Beytriige,” 9. 348. 
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