TONSILS. 



[ 773 ] 



TORULA. 



many of them in the latter medium forming 

 beautiful polarizing objects. 



The imperfectly cleansed tongues, when 

 stained with Judson's dyes, also form beau- 

 tiful objects. 



BIBL. Carpenter, Microscope', Thomson, 

 Todd's Cycl. An.SfPhys. iv. 1142; Ann. N. H. 

 2. vii. 86; Gray, ib. 2. x. 413; Macdonald, 

 ib. 1868, ii. 236, 1869, iii. 113; Maplestone, 

 3f. Mic. Jn. 1872, 45 ; Hogg, Tr. Mic. Soc. 

 1868 ; LovSn, (Efversiyt Kongl. Vetensk. Ak. 

 Forhandl. 1847 ; Troschel, Gebiss d. Schnec- 

 ken (36 pis,), 1875 ; Woodward, Mollusca. 



TONSILS. These organs may be re- 

 garded as consisting of from ten to twenty 

 follicular glands, resembling those found at 

 the root of the tongue, surrounded by a 

 common fibrous coat or capsule. 



The blood-vessels are numerous, forming 

 elegant networks around the follicles. (Kol- 

 liker, Hist. ; Klein & Verson, Strieker's 

 Hist.} 



TOPAZ. The crystals of this mineral 

 consist principally of silicate of alumina, 

 with the fluorides of aluminium and sili- 

 cium. 



Sections of topaz &c. often exhibit micro- 

 scopic cavities, frequently containing crys- 

 tals and one or two non-miscible liquids, 

 the latter sometimes including bubbles of 

 gas or vapour. 



Brewster recommended the spherical 

 cavities as the best objects for examining 

 the aberrations of lenses, and as infinitely 

 preferable to globules of mercury. 



BIBL. Brewster, Edinb. Phil. Tr. x. & 

 xvi. ; Microscope, 186. 



TORQUATEL'LA, Lankester. A 

 doubtful genus of Infusoria. Body rounded, 

 with an anterior funnel-shaped frill of un- 

 dulating membrane ; no cilia, vacuoles, or 

 nucleus. Marine, in Bay of Naples. (Lan- 

 kester, Qtt. Mic. Jn. 1874, 272.) 



TOR'TULA, Hedw. See BARBULA. 



TOR'ULA, Pers. A genus of Torulacei. 

 The plants ordinarily referred here appear to 

 be somewhat heterogeneous in their nature. 

 In what may be considered the true species, 

 the chains of spores form the principal bulk 

 of the plants, little or no filamentous myce- 

 lium existing. Other forms very generally 

 included under this head agree in their 

 characters with OIDITJM, which itself is a 

 doubtful genus, probably founded on the 

 conidiiferous states of more perfect kinds. 

 But in T. sacchan (or cerevisice), the Yeast- 

 fungus, usually referred here, we find both 



forms presented; for when actively vege- 

 tating in fermenting liquids, it presents the 

 characters shown in PI. 26. fig. 23, while, 

 while the liquid becomes exhausted, por- 

 tions of the fungus float to the top, and 

 produce a filamentous structure, terminating 

 in chains of spores, such as are represented 

 in PI. 26. fig. 24, and in fig. 756. The 

 simply beaded form is taken as the type of 

 a genus Cnjptococcus by certain authors, 

 some of whom consider it a Fungus, others 



Fig. 756. 



Torula sacchari (aerial form). 

 Magnified 200 diameters. 



(Kutzing especially) an Alga. The same 

 varieties of form occur in the Vinegar- 

 plant ; and in both cases Penicillium glau- 

 cum seems invariably to succeed the pre- 

 ceding when kept at a moderate tempera - 

 ture. Thus between all these various forms, 

 together with Oidium lactis, there appears 

 to be a relation, not yet clearly made out, 

 indicating that they probably represent 

 different states of the same plant grow- 

 ing under different conditions of nutri- 

 tion and temperature. Further remarks on 

 this head are made under YEAST and VI- 

 NEGAR-PLANT. A growth similar to T. 

 sacchari presents itself sometimes in decom- 

 posing urine (PI. 26. fig. 7) from healthy 

 subjects ; and indeed scarcely any decom- 

 posing animal or vegetable fluid, in which 

 there exist fermentible elements, remains 

 long free from Torula-like growths, if left 

 exposed to the air (see FERMENTATION). 



We find it impossible to give definite 

 characters for the species that have been 

 enumerated. T. herbarum is a common 

 form growing on decaying stems of plants ; 



