SPUMELLA. 



[ 728 ] 



STAINING. 



(Reticularid), pi. 280; Fries. Sum. Vey. 

 449. 



SPUMEL'LA, Cienk. A genus of Fla- 

 gellate Infusoria. Minute, free or pedicled, 

 rounded or ovate, mouthless, with 1 long 

 and 2 short flagella. 8. cjuttula and 8. vim- 

 para = Monas g. and v . , Ehr. In pond water 

 and infusions. (Kent, Inf. 305.) 



SPUTUM. We omitted to notice under 

 EXPECTORATION the occurrence of fibrinous 

 casts of the smaller bronchi and pulmonary 

 air-cells in the expectoration of pneumonia. 

 They are best seen on mixing the sputa with 

 water, forming dichotomous cylinders with 

 rounded enlargements. They consist of fine 

 filaments, and are mostly covered with gra- 

 nule-cells, and are generally met with be- 

 tween the third and the seventh day. 



Koch's. Bacillus tuberculosus of phthisis, 

 also deserves special attention. 



BIBL. Remak, Diagn. fyc. Untersuch., Ed. 

 Mn. Jn. 1847, vii. 350; Gibbes, Lancet, 

 1882, ii. 183 & 797 ; Jn. M. Sac. 1882, ii. 

 572. 



SPYRID'IA, Harv. A genus of Cerami- 



Spyridia filamentosa. 

 Fragment with a favella and ramules. 

 Magnified 25 diameters. 



aceae (Florideous Algae), containing one 

 British species, S. filamentosa (fig. 693), 

 having a dull-red, cylindrical, filiform, 

 much -branched frond, consisting of a cham- 

 bered tube, the articulations of which are 

 short, and the walls of which are composed 

 of small angular cells. It arises from a 

 broadly expanded disk. The branches are 

 clothed with setaceous ramules. The 

 favella are stalked, gelatinous, and lobed, 

 surrounded by a few ramules and contain 

 two or three masses of spores. The tetra- 

 spores occur attached to the ramules. An- 

 theridia have not yet been observed. 



BIBL. Harvey, Mar. Alg. 166, pi. 22 D. 



SQUAMA'KIA, DC. A genus of Placo- 

 dei (Lichenaceous Lichens) . Six species, 

 on calcareous rocks and earth. (Leighton, 

 Lich. Fl. 157.) 



SQUAMEL'LA, Bory, Ehr. A genus of 

 Rotatoria, of the family Euchlanidota. 



Char. Eyes four, frontal; foot forked; 

 freshwater. 



8. oblonga (PL 44. fig. 29). Carapace 

 depressed, elliptical, or ovate-oblong, hya- 

 line ; toes slender, long ; length 1-216". 



S. bractea. Toes short and thick. (Ehr. 

 Inf. 479.) 



'SQUAMULI'NA,Schultze. An obscure, 

 small, parasitic, scale-like, opaque Forami- 

 nifer, probably Nubecularian. 



BIBL. Schultze, Org. Polyth. 56; Car- 

 penter, For. 67. 



STACHEI'A, Brady. An adherent Are- 

 naceous Foraminifer, with numerous subdi- 

 vided chambers, acervuline or in irregular 

 lavers. Six fossil species (Carboniferous). 

 (Brady, Carbonif. Foram., Pal. Soc. 1876, 

 107.) 



STAOHYLTO'IUM , Link. A genus of 

 Mucedines (Hyphomycetous Fungi), nearly 

 related to Botrytis, distinguished apparently 

 only by the subpedicellate spores. Fries 

 states that these are developed within a 

 fugacious veil (?). BOTBYOSPOBIUM dif- 

 fusum, Corda, is included here by most 

 authors. S. bicolor and 8. terrestre, 'having 

 quaternate sporiferous branches at the upper 

 joints of the erect, simple filaments, grow 

 upon decaying herbaceous plants and rotten 

 sticks. 



BIBL. Berk. Br. Fl. ii. pt. 2. 341 ; Fries, 

 Sum. Veg. 490; Greville, Crypt. Flor. pi. 



STAINING. The staining or dyeing 

 process was introduced by Geiiach, after 

 observing in his carmine injections, how 

 differently the elements of the tissues were 

 dyed by the colouring-matter. 



The general action of the dye is, that the 

 nuclei and the protoplasm of the cells are 

 deeply coloured, while the cell-walls are 

 but little acted upon, and the intercellular 

 substance is hardly at all affected. The 

 cause of this difference in the dyeing effect 

 lies partly in the physical and partly in the 

 chemical condition of the organic matter. 



If the dye-liquor be too strong, or its 

 action too long continued, the whole tissue 

 will become confusedly coloured, and its 

 elements undistinguishable. 



The dyes which have been used are very 



