Physiology of Animals. 65 



deeper foundation possible. ' * The dawn of the new 

 era", Prof. Greenfield says, "may be traced to the 

 beginning- of the present century, and may be said to 

 have begun with new ideas of structural anatomy pre- 

 ceding the fuller knowledge of function. For, until the 

 primary analysis of the structure of the body had been 

 made, until the minuter elements had been grouped into 

 classes, and their individual functions and powers deter- 

 mined, it was impossible to reduce to any general ex- 

 pression the derangements to which they were subject. 

 The first step to this was the re-arrangement and classi- 

 fication of the tissues, due partly to Haller, but mainly 

 to the genius of Bichat, who must be regarded as the 

 founder of general morbid anatomy, as well as of general 

 anatomy. He not only classified the tissues and organic 

 systems, but he entered into their pathology, and as- 

 serted that 'each tissue has its own diseases'." Mere 

 localization of disease in organs was demonstrably in- 

 sufficient after Bichat had shown that different tissues 

 in the same organ might be the seat of different patho- 

 logical changes. 



(4) But analysis could not long rest at the level of 

 tissues, and the formulation of the cell-theory marks a 

 new era in the history of pathology. Johannes Miiller, 

 who moved on so many different lines of research, at- 

 tacked the problem of the histology of tumours; and 

 Goodsir was, in Virchow's words, " one of the earliest 

 and most acute observers of cell-life, both physiological 

 and pathological ". 



To F. G. J. Henle (1810-1885) belongs the credit of 

 having founded the Modern Pathology which Virchow 

 took the lead in developing. A pupil of Johannes Miiller, 

 and contemporary with Schwann, he published in 1846 

 a Manual of Rational Pathology, in which he systema- 

 tized, in their physiological relations, the facts then 

 known, maintaining for the first time clearly that " phy- 

 siology and pathology are branches of the same science". 

 He should also be remembered for his remarkable pre- 

 vision (1840), that contagious diseases must be due 

 to ' ' parasitical beings which are among the lowliest, 

 smallest, but at the same time most productive which 



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