32 
t>. P. YONKEKMAN. 
otherwise accumulated before the court and the public. It is, 
therefore, essential that he should have clear views as to what 
constitutes evidence, and, on the other hand, what is inadmissible 
as evidence. It is often a matter of regret that veterinary sur¬ 
geons neglect the study of the rules of evidence, and suffer accor¬ 
dingly. The rule generally laid down is, that “ no evidence can 
be given foreign to the question or points at issue,” and this sug¬ 
gests a word on the relationship between the evidence given by 
an expert and the functions of the jury, which latter are not to be 
usurped by the former—for instance: In a case of suspected 
poisoning, the surgeon stated that certain symptoms he noted and 
described were consistent with poisoning with strychnia. In that 
connection this question was ruled improper: “ Do you consider 
these symptoms were the result of the exhibition of strychnia ? ” 
but the following was allowed: What in your opinion was the 
cause of the symptoms that you say were consistent with poisoning 
from strychnia?” The first question the jury were there to de¬ 
cide; the second was only the opinion of the medical expert, and 
did not userp the jury’s duty. 
As a general rule, hearsay is not evidence. The law believes 
no man’s bare assertion, but there are exceptions to this rule, as 
pedigrees, prescriptions and customs; the statements of the dead 
are admitted as the only means of getting at the facts. 
Evidence may be sincere without being true, for instance: A 
man honestly believes an animal to be sound, and so testifies; but 
future developments proved it unsound unknown to the man. 
Evidence is of two kinds ; Positive or Direct, and Circumstan¬ 
tial. Thus if an expert says, am certain the lungs were dis¬ 
eased, for I saw them;” then that fact is proved as far as a fact is 
capable of proof. But if he says, “ To the best of my belief the 
lungs were diseased,” explaining at the same time that owing to 
lack of proper examination or other existing circumstances he is 
not certain, it is circumstantial evidence. 
Thus we must, as expert witnesses, always bear in mind that 
we are called no to usurp the functions of the jury in venturing 
to decide the case submitted to them and them only, but merely, 
as far as we can, to assist them in their deliberations. 
Scientific or expert witnesses may be called either as common 
