INTRODUCTION. 



1. THE doctrine of the elementary structure of Plants and Animals, 

 belongs to the last two centuries, originating with Marcellus Malpighi 

 (1628-94), and Anton van Leeuwenhoek (1632-1723), at the period 

 when the assistance of magnifying glasses, powerful, though of very 

 simple form, was first offered to observers. The ultimate constituents 

 in respect of form, of organisms, were unknown to antiquity and to the 

 middle ages, for although Aristotle and Galen speak of the homogeneous 

 and heterogeneous parts of the body (partes similares et dissimilares), 

 and Fallopius (1523-62) defined still more exactly the idea of " Tissues," 

 and even attempted to classify them ( 4 Tractatus quinque de partibus 

 similaribus,' opera, torn. ii. Francof. 1600), yet the minuter structures 

 were completely hidden from these investigators. Brilliant as were the 

 first efforts of the young science under the guidance of these men and after- 

 wards of a Ruysch, Swammerdam, and others, yet they were not adequate 

 to acquire a safe footing for it, since, on the one hand, the philosophers 

 were far too little masters of microscopic investigation to strive at once, 

 with a clear insight, towards the true goal ; while, on the other, the deve- 

 lopment of other branches of study, as of the grosser Anatomy, of Physio- 

 logy, of Embryology, and of Comparative Anatomy, claimed too large a 

 share of their attention. It thus happened that, with the exception 

 of a few to some extent important works (Fontana, Muys, Lieberkiihn, 

 Hewson, Prochaska), Histology made no considerable progress during 

 the whole of the 18th century, and acquired no importance greater than 

 that due to a disjointed collection of isolated observations. It was in 

 the year 1801 that it first acquired a rank co-equal with that of its 

 sister anatomical sciences by the genius of a man to whom indeed, Histo- 

 logy owes no great discoveries, but who understood, as no one before 

 him had done, so to arrange existing materials and so to connect 

 them with Physiology and Medicine, that for the future its independence 

 was assured. In fact, Bichat's ' Anatomic GeneVale' (Paris, 1801), 

 was the first attempt to treat Histology scientifically, and on this ac- 

 count merely, it constitutes an epoch ; but besides this, its importance 



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