PREFACE. 12 



lion of the mass of disease in the ordinary method. 

 Microscopic agency, in thus assisting the medical man, 

 contributes much to the alleviation of those multiplied 

 " ills which flesh is heir to." So fully impressed were the 

 Council of the Eoyal College of Surgeons with the import- 

 ance of the facts brought to light in a short space of time, 

 that, in 1841, they determined to establish a Professorship 

 of Histology, and to form a collection of preparations of 

 the elementary tissues of both animals and vegetables, 

 healthy and morbid, which should illustrate the value of 

 microscopical investigations in physiology and medical 

 science. From that time, histological anatomy deservedly 

 became an important branch of the education of the 

 medical student. 



In the study of Vegetable Physiology, the Microscope 

 is an indispensable instrument ; it enables the student to 

 trace the earliest forms of vegetable life, and the functions 

 of the different tissues and vessels in plants. Valuable 

 assistance is derived from its agency in the detection of 

 adulterations. In the examination of flour, an article of 

 so much importance to all, the Microscope enables us 

 to judge of the size and shape of the starch-grains, their 

 markings, their isolation and agglomeration, and thus to 

 distinguish the starch-grains of one meal from those of 

 another. It detects these and other ingredients, invisible 

 to the naked eye, whether precipitated in atoms or aggre- 

 gated in crystals, which adulterate our food, our drink, 

 and our medicines. It discloses the lurking poison in 

 the minute crystallisations which its solutions precipitate. 

 " It tells the murderer that the blood which stains him is 

 that of his brother, and not of the other life which he 

 pretends to have taken ; and as a witness against the 

 criminal, it on one occasion appealed to the very sand on 

 which he trod at midnight." 



