MORBID GROWTH IN GENERAL. 81 



demarcation ; to this peculiarity it owes its occasional name of 

 *^ insular intumescence." It occurs in the course of many 

 chronic inflammations of the skin and of the arterial coats, in 

 enteric fever, and in many forms of cancer. 



6. A TUBER. The area occupied by the base of any cir- 

 cumscribed swelling remaining constant, its progressive increase 

 in heicfht makes it more and more of a tuber. The outline and 

 heio-ht of a tuber may vary within certain limits ; when much 

 elongated it is termed a wart {papilla). The base of a tuber, 

 however, always remains its broadest part. Should its base be 

 nari'owed its edges necessarily come to overhang it, and the 

 irrowth becomes — 



7. A FUNGUS ; or, 



8. A PEDUNCULATED TUMOUR (jpolypus). The distinction be- 

 tween a fungus and a polypus depends essentially on the mode 

 in which the constriction at the base of the tuber is brought 

 about. Should this be merely relative, i.e. due to excessive 

 proliferation In the distal portion of the tuber, we call the growth 

 a fungus. The fungus has a broad pedicle and a flattened top. 

 Should this relative narrowing of the base be associated with an 

 absolute contraction, by the dragging of the head as its size 

 increases, whether by its own weight or the application of 

 external force, the base gets narrowed down to a relatively thin 

 stalk, and a polypus is the result. 



9. A CAULIFLOWER GROWTH. ThIs Is undoubtedly the most 

 complex form which can be evolved from a circumscribed eleva- 

 tion of the surface. As its name imphes. It is constructed on a 

 dendritic type. We have a trunk which gives off* branches at 

 different angles; on the smallest twigs we occasionally have 

 leaves or berries. Glands w^ith branching ducts are similarly 

 constructed (those known as acinous glands). The analogy 

 between the first mapping out and early development of these 

 glands and that of the dendritic vegetations from cutaneous and 

 mucous surfaces is very sti'iking. AVe shall return to It more at 

 length when we come to speak of these growths in detail. 

 Suffice it for the present to say that in the dendritic outgrowths, 

 as in the acinous glands, the essential part of the entire forma- 

 tion is to be sought in the ultimate elements of their structure. 

 And here the ultimate element is the elongated tuber — the 

 I)apllla. And indeed no other view harmonises so well with the 



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