INFLAMMATION. 



[ 414 ] 



INFUSORIA. 



cells are the least stable, and are the first 

 to multiply. Possibly the age of the cells 

 may influence their tendency to become 

 active, the newer being less stable than the 

 older elements. In all cases, however, the 

 rapidity and extent of the proliferation are 

 in direct proportion to the intensity of the 

 inflammation. The earliest nutritive change 

 is thus one of cell-proliferation ; the subse- 

 sequent ones are characterized either by im- 

 pairment of nutrition and the degeneration 

 and death of the newly formed elements, 

 or by the development of these into a per- 

 manent tissue. The more intense the in- 

 flammation the greater is the rapidity of 

 the cell-proliferation, the more abortive are 

 the young cells, and the less is their ten- 

 dency to form a permanent tissue. In con- 

 nective tissues these changes in the cells 

 are necessarily accompanied by changes in 

 the intercellular substance. The latter are 

 for the most part characterized by softening. 

 In common connective tissue the fibres in 

 the first place become succulent and less 

 distinct, and ultimately they are completely 

 destroyed ; in cartilage the matrix softens 

 and liquefies ; in bone the lime-salts are 

 removed, the lamellae disappear, and the 

 osseous structure becomes converted into 

 medullary tissue. Hence the destructive 

 effect of the inflammatory process. 



Those retrograde cells which undergo 

 fatty degeneration, are known as exudation 

 corpuscles (PI. 38. fig. 7). 



The inflammatory exudation, consisting 

 of emigrant cells, which often undergo fis- 

 siparous multiplication, of the proper cells 

 of the inflamed tissue, which undergo in- 

 crease of size and numbers, and of the fibri- 

 nated liquor sanguinis, may undergo reso- 

 lution, organization, suppuration, and organi- 

 zation after suppuration : 



Resolution, by distribution of the emigrant 

 cells over a wider area, and their return into 

 the lymphatics, and by a process of fatty 

 degeneration of the cellular elements. 



Organization, by the timely development 

 of blood-vessels, and the conversion of the 

 exudation into fibrillar connective tissue. 

 The cells which are not devoted to the 

 formation of blood-vessels, grow spindle- 

 shaped, and are so closely packed that they 

 give rise to a new variety of tissue. It 

 forms cylindrical or slightly flattened bun- 

 dles which interlace. 



Suppuration. See Pus. 



BEBL. Works on Medicine ; Lebert, Phys. 

 Pathol. ; Wedl, Path. Hist. ; Forster, Path. 



An. ; Gluge, Atlas Path. An. ; Lister, Inf,., 

 Phil. Trans. 1859 ; Cohnheim, Virchows 

 Archiv, xl. 1, and Entzundung, 1873 ; 

 Strieker, Qu. M. J. x. 242: Cornil and 

 Ranvier, Hist. Path.; Inflam., Holme's Xyst. 

 Surg. i. and Append. ; Virchow, Cell. Path. ; 

 Rin'dfleisch,Pa^. Geivebel.1878; Green,P<A 



INFUNDIBULA'TA. An order of Po- 

 lyzoa. (See POLYZOA.) 



INFUSO'RIA. A class of Protozoa. 



Char. Microscopic animals not furnished 

 with either vessels or nerves, but exhibiting 

 internal spherical cavities ; motion effected 

 by means of cilia, or variable processes 

 formed of the substance of the body, true 

 legs being absent. (Body composed of pro- 

 teine compounds ; soluble in solution of 

 potash.) 



Every one who has examined with a 

 microscope a drop of water containing ani- 

 mal or vegetable matter which has been set 

 aside for a time, or a drop from any pool or 

 ditch, must have observed numerous minute 

 beings in active motion, resembling some of 

 those figured in Pis. 30, 31, & 32 ; these are 

 Infusoria, or the animalcules of infusions. 



Perhaps no question has been more dis- 

 cussed than that of the structure of the In- 

 fusoria. Ehrenberg regarded them as being 

 highly organized, and furnished with distinct 

 organs like the higher animals j whilst some 

 more recent authors consider them as re- 

 presenting simply a nucleated cell. Unfor- 

 tunately the facts are not accordant with 

 either of these views, and the question must 

 be considered as still sub judice. 



The more or less flexible body of the Infu- 

 soria is usually covered with vibratile cilia, 

 which appear to spring from a cuticle. They 

 are sometimes collected in a circle around 

 an opening or mouth, which leads to a gullet 

 terminating in the soft sarcode of the centre 

 of the body. This central portion of the 

 granular and otherwise structureless sarcode 

 is surrounded by a denser or cortical layer, 

 which underlies also the cuticle. In the 

 cortical layer are the vacuoles and the nu- 

 cleus and nucleolus ; whilst in the inner 

 mass are the spaces which are produced by 

 the ingestion of food and water, and which 

 have been termed stomachs, whence the 

 former name, the Polygastrica. There is a 

 rotatory movement of the soft sarcode sur- 

 rounding these digestive spaces, which 

 causes them to change their positions before 

 they disappear. The animalcule moves 

 some of its cilia voluntarily ; others appear 

 to be in constant movement, and they are 



