72 
by chemical agents, are also recognisable by the aid of the 
microscope, and it is in cases where only small quantities of 
the fluids suspected to contain the poison can be procured 
for inspection that the microscope lends its invaluable aid. 
We give from Dr. Taylor’s book illustrations of the crystals 
of acetate of lead and oxalic acid as seen under low powers 
of the microscope. 
Hie: 8: 
Acetate of lead magnified 30 Oxalic acid magnified 30 
diameters. diameters. 
Were it our object here to give an exhaustive account of 
where the microscope can be used with advantage in medical 
jurisprudence, we could from the pages of Dr. Taylor’s work 
show how large a number of other mineral poisons may be 
detected most successfully by itsaid. The salts of potassium, 
sodium, barium, and strontium have all occasionally acted as 
poisons, and the definite forms which these salts assume even 
when crystallised from the weakest solutions are far more 
secure guides than any mere chemical analysis. 
We follow, however, Dr. Taylor in his illustrations, and 
arrive at the group of poisons, which in their separated forms 
are known as vegetable alkalies and alkaloids. Here we 
have a series of substances which from the earliest times have 
been known to exert the power of destroying life. Although 
we have to thank chemistry for revealing to us a knowledge 
of the existence of these substances in plants where poisonous 
powers have been known in all countries and in all times, it 
is to the microscope that we are indebted for a knowledge 
of the fact that these alkalies and alkaloids have definite 
forms by which their presence may be detected in much more 
minute quantities than by the aid of chemical analysis. We 
know that this position may be controverted by the chemist, 
but we know that it could be only controverted by the 
chemist who is destitute of that ability to use the microscope 
