276 the president's address. 



and passes on to atrophy, selecting for " atrophy with degeneration ' 

 the fall of the leaf. Here is interpolated a note on liquefactive 

 degeneration, diseases associated with degeneration. " Such," he 

 says, "are the gum disease (gummosis), the resin-flux (resinosis), 

 and others of the same group, which I find classed as liquefactive 

 diseases, and in which cell-walls, wood, and other structures dis- 

 solve in, or into morbid products. I venture to guess that these 

 may give help in the study of our mucoid and other liquefactive 

 degenerations." 



Passing over many curious analogies, we encounter a contrast, 

 with a subsidiary analogy, in " repair of injuries." " Let me," he 

 says, " relate one case. A fir tree, fifty years old, had a large piece 

 of bark stripped from its trunk. The wound extended round nearly 

 a fourth of the circumference of the trunk, and laid bare the wood. 

 It was not dressed or guarded ; the outer layer of the exposed 

 wood died as usual, and then every year the successive annular 

 growths of new wood and bark extended a little further over the 

 bared place. In one hundred and fifty years these growths met 

 and coalesced, and the wound was covered in. When the tree was 

 felled and cut through at the injured part, where there was still a 

 deeply-depressed scar, the concentric rings of wood proved the 

 growth of fifty years before and one hundred and fifty after 

 the injury, and even now the healing was not complete ; there was 

 still a cavity between the old wood and the new ; the healing was 

 not such as we should call good in any similar case in an animal. 

 Still, there was healing ; the i intention ' was maintained for a 

 century and a half." 



From the processes of repair Sir James passes to inflammation. 

 " The likenesses between the inflammations in plants and in animals 

 are best shown in their visible structural changes, and these have 

 been admirably traced by Waldenburg. He has applied various 

 irritants to leaves, fruits, and stems, such as foreign bodies, setons, 

 crushings, cauteries, and others. The results, speaking very 

 generally, are that, as in ordinary wounds, the cell structures 

 actually involved in the injury perish aud dry up ; that those most 

 nearly adjacent suffer degeneration, indicated by their protoplasmic 

 contents becoming turbid and their chlorophyll becoming yellowish 

 or brownish, while in those next to them, and within distances 

 varying according to the injury and the texture of the part injured, 

 enlargement of cells ensues, and increase by division and thickening 

 of the cell-walls. In these changes you may study, with compara- 



