EXTRACTS FROM EXCHANGES. 
711 
animals I have operated on have their tails in good shape, 
carried well, and useful as a protection. 
I have tried the experiment on seven animals, and in two 
cases my work was futile, but I blame myself and the owner 
for the failure, as the patients were far out in the country. In 
those cases the beasts became less vicious, but did not carry a 
good tail. 
EXTRACTS FROM EXCHANGES. 
GERMAN REVIEW. 
By Prof. Olof Schwarzkopf, Flushing, N. Y. 
Observations on the Sterility of Mares. —Frock- 
Schlesarz demonstrates in a lengthy and interesting article on 
the subject that in Schleswig 30 per cent, of the breeding mares 
remain unproductive. He cites the report from other countries, 
notably of France (50 per cent.), and thinks that this result in 
breeding mares is altogether out of proportion to the other do¬ 
mestic animals. In examining the causes he admits that the 
fault lies at times wdth the stallion, and cites instances where 
government stallions produced no offspring at all, or for certain 
periods, then again they became productive. In one case he 
found on microscopic examination that the semen of a stud¬ 
horse contained no spermatozoa. But he believes that the ordi¬ 
nary cause is to be found in the mares themselves; they were 
expected to perform regular and often hard work in the times 
intervening to breeding, that thus their generative apparatus be¬ 
came weakened, resulting in irregular periods-of heat, and that 
too often old and w T orn-out mares were put to breeding. He 
goes at length into a consideration of the chronic catarrhs of 
the vagina and uterus, so frequently found in old breeding 
mares, but contends that the most common cause of sterility of 
mares is a stricture of the orificium uteri, which promptly yields 
to operation and treatment. He has practised artificial impreg¬ 
nation, but considers it as yet an uncertain method, certainly 
not always satisfactory. His observation is that mares so im¬ 
pregnated carry their foetus from 10 to 14 days above the typi¬ 
cal periods of pregnancy.—( Berlin . Th. Woc/i.) 
The Colic of Horses from a Genetic and Therapeu¬ 
tic View. —Dryneau has extensively experimented with meth- 
