75 
the utmost importance in our criminal courts is the investi- 
gation of the clothes and persons of murderers, and the 
suspected instruments of murder with the microscope. Here 
a knowledge not only of vegetable but of animal histology is 
of the greatest importance. The presence of a cotton hair 
or linen fibre, or a human hair upon a knife or other instru- 
ment, may by identity with the clothes or hair of a murdered 
person become a link in the chain of evidence. The presence 
of a human hair under a nail in the sole of a boot has con- 
nected the owner of the boot with the crime of trampling on 
the face of the dead person he has murdered. The examina- 
tion of mud and dirt on clothes has connected suspected 
persons with the mud and dirt of the ground where persons 
have been found murdered. Ina case near Hull the skilful 
microscopists of that town showed in the presence of pecu- 
liar forms of diatomacee on the sole of a boot that the 
possessor had been at the spot where a dead man lay murdered. 
Of all the applications of the microscope to criminal cases, 
the detection of the stains of human blood have gained the 
most interest in the public mind. Ever since the discovery 
of the persistent character of blood-globules the investigation 
of the nature of blood-stains has occupied the attention of 
microscopical observers. Unfortunately, however, for medical 
jurisprudence, the human blood-globule cannot always be 
distinguished from the blood stains of the lower animals. 
From a vast number of investigations, more especially those 
Fie. 15. 
Blood-globules, 319 diameters. 
a. Of the horse. 6. Of the sheep. c. Of the common fowl. d. Of the 
salamander. 
of Mr. Gulliver, the size of the blood-globules of a large 
number of the lower animals has been ascertained. Where 
the size or the form of the blood-globules of the lower animals 
differ much from the human globule they may be dis- 
