TUBER. 



[ 785 ] 



TUBERCULAKIA. 



one side thin, undulating, frill-like ; ante- 

 riorly produced into a long ilagellate appen- 

 dage ; no nioulh. 



T. sa>i(/ id Ill's, in frog's blood, length 

 1-600"; f. Eberfhi, in the intestines of 

 poultry. (Grubv, Covipt. Rend. 1843 ; Kent, 

 Inf. 2l8.^ 



"TUBER, Mich. See Tuberacei. 



TUBERA'CEI.— A family of Ascomyce- 

 tous Fungi, growing underground or upon 

 the siu'face, of more or less round form, and 

 solid, fleshy texture, excavated with sinuous 

 cavities liied by asci containing usually 

 four or eight spores, elegantly reticidated 

 or spinulose (figs. 768-770). The internal 



Fig. 768. 



Choiromyces leonis. 



Fig. 768. A peridium. Nat. size. 

 Fig. 769. An ascus with spores. Magnified 400 dia- 

 meters. 

 Fig. 770. Vertical section of a peridium. 



substance either dries and grows hard, or 

 falls into a floccident powder with age. 



Tuber cibarium is the common truffle. 

 Sections of the marbled internal substance 

 show this to be composed of interlacing 

 branched filaments, forming fleshy convo- 

 lutions, between which serpentine cavities 

 are alternately excavated ; branches of the 

 filaments free at the sm-face of the lacunae 

 bear spherical sacs {asci), each containing 

 four globular spores of yellow-brown colour, 

 having an elegantly reticulated outer coat. 

 Wlien the spores germinate, they produce 

 a subterraneous cottony myceUum, which 

 after a time presents villous nodides, in the 



interior of which the peridia are developed ; 

 as these advance, the villous coats gradually 

 vanish, together with the mycelial structure, 

 and the mature peridia appear free, either 

 a little beneath (Tuber cibarium) or upon 

 the surface {T. album) of the soil (see also 

 Elaphomyces). 



BiBL. Berk. Br. Fl. ii. pt. 2. 227; Tulasne, 

 Ann. Sc. Nat. 2. xvi. o ; Monog. Fumj. Hij- 

 po(jcBi, 1851 ; Ann, N. H. 2. viii. 19 ; Les- 

 piault, Ann. Sc. Nat. 3. ii. 316 ; Vittadini, 

 Monog. 2\iber. ; Monog. Lycopocl., Mem. 

 Turin{Acad. 2. v. 145. 



TUBERCLE or Tubercitlar jiatter. 

 — Tubercle consists of lymphatic corpuscles 

 contained in the meshes of a very delicate 

 reticulum, or a transparent homogeneous 

 tissue (PL 38. fig. 8). The cells vai-j^ in 

 size, and many contain a small distinct 

 nucleus. In addition to these, there are a 

 few larger cells containing two or even three 

 nuclei. The nucleated cells are exceedingly 

 destructible, so that often more fi'ee nuclei 

 than ceUs are visible. In most cases the 

 tubercle appears to consist entirely of closely 

 crowded nuclei or so-called tubercle-cor- 

 puscles (PI. 38. fig. 9 a), about 1-5000 to 

 1-4000" in size, oblong-angular, and un- 

 affected or simply rendered paler by acetic 

 acid (fig. 9 b). 



Tubercle appears to originate most fre- 

 quently fi'om the tissue which surrounds the 

 small arteries in every situation, constituting 

 the lymphatic sheaths. The small cells in 

 this situation multiply at separate centres, 

 and thus miliary nodules are produced 

 aroimd the vessel ; and as they gradually de- 

 velope, they compress the vessel, and may 

 finally occlude it. Tubercle invariably 

 imdergoes a retrogressive change ; this com- 

 mences in the centi'e of the grauidations, 

 and consists in the atrophy and incomplete 

 fatty metamorphosis of the closely crowded 

 cellidar elements, constituting what is 

 termed caseation. The translucent and grey 

 granulations thus become opaque and yel- 

 lowish, the yellow tubercle being merely a 

 stage of the grey granulation. The caseous 

 tubercle subsequently softens, or may gra- 

 dually dry up into a firm cheesy mass, which 

 becomes ultimately calcified. 



BiBL. Green, Path. Anat. 1871, 145; 

 Rindfleisch, Path. Hist. 1878. 



TUBEROULA 'RIA, Tode.— A supposed 

 genus of Stilbacei (Hyphomycetous Fungi), 

 but apparently only preparatory forms of 

 Sphseriaceous Fungi. T. vulgaris is a state 

 of Nectria (Sphceria) cinnabarina ;' it is ex- 



3e 



