BROOD-CAVITIES. 445 



in the body which are indeed much less well known, and 

 of which the special peculiarities cannot as yet be seized 

 with such great precision. These are processes, where 

 we see endogenous changes set in in the interior of pre- 

 existing cells. In a simple cell a vesicular cavity forms, 

 which, contrasted with the somewhat cloudy and gene- 

 rally slightly granular contents of the cell, presents a 

 very clear, bright, homogeneous appearance. In what 

 manner cavities of this first kind, which I class together 

 under the name of physatidss, arise, is not yet altogether 

 certain. The greatest probabilities are in favour of the 

 nuclei being, in certain forms, likewise the starting-point 

 of these formations. For, beside these cells, others are 

 seen with two nuclei, one of which, in several of them, 

 has become somewhat larger and brighter than usual, 

 though still preserving the character of a nucleus. Sub- 

 sequently, this vesicle becomes so large that the cell is 

 gradually almost entirely filled with it, and its former 

 contents with the nucleus only look like a little appen- 

 dage to the vesicle. So far the process is tolerably sim- 

 ple. But besides these vesicles, thus growing and filling 

 the cells, others are met with, in the interior of which 

 elements of a cellular nature are enclosed. This is of 

 pretty frequent occurrence in cancerous tumours, but 

 also in normal parts, for example in the thymus gland. 

 This form seems to indicate, that in fact by means of a 

 process which cannot be directly traced to any division 

 of the pre-existing cells, and indeed in peculiar vesicular 

 cavities (which I have named brood-cavities (or -vesicles 

 Brutraume), ) in the interior of cellular elements, new 

 elements of a similar kind may be developed. How- 

 ever, this is at all events a condition which plays but a 

 subordinate part in the whole history of new-formations ; 

 the regular form is the one first described. There are 

 only a few pathological new-formations, in the history of 



