MICROHALOA. 



[ 426 ] 



MILK. 



MICROHALOA, Kiitz. A genus of Pal- 

 mellacese (Confervoid Algae). An obscure 

 product. Kiitzing states that Hassall's 

 Sorospora virescens belongs here. There 

 does not seem to be any ground for separa- 

 ting this from PALM EL LA. 



BIBL. Kiitz. Sp. Alg. p. 207, Tab. Phyc. 

 pis. 6, 7 ; Hassall, Brit. Fr. Alg. p. 326. 

 pi. 78. fig. 8 a. 



MICROMEGA, Ag. A genus of Diato- 

 maceae. 



Char. Frustules arranged in longitudinal 

 rows within gelatinous tubes or surrounded 

 by slender curved or crisped fibres ; these 

 being enclosed in other gelatinous tubes, 

 forming filiform branched fronds; valves 

 resembling those of Navicula. Marine. 



Kiitzing notices the occurrence of spo- 

 rangia or sporange-like bodies (spermatia) 

 filled with the frustules, within the substance 

 of the sheaths, and formed " from the dila- 

 tation of the naviculae " (frustules) ; but the 

 exact nature of the process is not described 

 nor understood. This formation of brood- 

 sporangia, as they might be called, would 

 appear to resemble that occurring in the 

 Desmidiacese (PI. 6. fig. 3 Ac?). 



Kiitzing describes twenty-eight species, 

 and divides them into two sections ; in one 

 the filaments being slender and capillary, 

 in the other rigid, cartilaginous and thicker. 



M.parasiticum (PI. 13. fig. 8; b, portion 

 of a filament magnified ; c, side view, d, 

 front view of frustule). Filaments slender, 

 wavy, tufted, cartilagino-gelatinous, yellow- 

 ish (sometimes brown), much branched, 

 capillary ; frustules crowded ; length of 

 frustules 1-1380". 



Parasitic upon larger marine algae. 



BIBL. Kiitzing, Bacill. p. 116, Sp. Alg. 

 p. 105. 



MICROMETER. See INTRODUCTION, 

 p. xxiv, and MEASUREMENT. 



MICROPERA, Lev. A genus of Sphae- 

 ronemei (Coniomycetous Fungi), of which 

 one species is described as British, M. dru- 

 pacearum (Cenangium Cerasi, junior, Fr., 

 Sphceria dubia, Pers.), growing on dead 

 branches of the cherry-tree. It forms 

 whitish tubercles which split the bark trans- 

 versely, composed of somewhat cylindrical 

 conceptacles, conjoined at the base, the 

 white mealy ostiole projecting; the linear 

 spores are yellowish and curved at the apex. 



BIBL. Berk, and Broome, Ann. Nat. Hist. 



2 ser. v. 380; Leveille, Ann. des Sc. nat. 



3 ser. v. p. 283 ; British Flora, ii. pt. 2. 

 p. 211. 



MICROSCOPE. The first twenty-six 

 pages of the INTRODUCTION consist of 

 remarks upon the microscope and micro- 

 scopic apparatus. 



MICROTHECA, Ehr. A marine organ- 

 ism of doubtful nature, placed by Ehren- 

 berg first among the Rotatoria, and subse- 

 quently with the Desmidiaceae, to neither of 

 which does it seem to bear the least resem- 

 blance. 



It consists of yellow, flattened, rectangular 

 (side view) bodies, with four equidistant 

 spines projecting from each end ; the colour 

 arises from the contents ; no transverse line 

 of division; entire length 1-216". 



Does it consist of the ovum of some 

 marine animal ? 



BIBL. Ehrenberg, In/us, p. 164. 



MIELICHHOFERIA, Hornsch. A 

 genus of Bryaceous Mosses, containing one 

 British species, sometimes referred to 

 Weissia (fig. 85, p. 100). 



Mielichhoferia nitida, Hsch. = Weissia 

 Mielichhoferia, Schwag. 



MIGNONETTE. Reseda odorata, be- 

 longing to the Dicotyledonous order Rese- 

 daceae. Its seeds are elegant opake objects 

 under a low power. 



MILK. This liquid consists of a solution 

 of caseine and certain salts, holding in suspen- 

 sion minute globules of fatty matter (butter). 



The fluid portion possesses no microscopic 

 peculiarities. The globules are very numerous, 

 round, and vary in size from mere molecules 

 to 1-3000 or 1-2000" in diameter. Each is 

 surrounded by a pellicle or coat of caseine, 

 which prevents the globules from fusing 

 into each other. If a portion of a drop of 

 milk be placed upon a slide, and fhe thin 

 glass cover be moved to and fro, the coat of 

 caseine will be ruptured, the globules of oil 

 will become confluent, and shreds of the 

 coats will be visible. If acetic acid be added, 

 the coats will be acted upon, and the con- 

 fluence also produced. The same effect 

 occurs naturally in sour milk; hence in this 

 the globules are often much larger than the 

 above dimensions, and irregular in form, 

 frequently becoming elongated and united 

 in twos, so as to bear some resemblance to 

 the young state of a fungus. 



The milk first secreted after parturition, 

 called the colostrum, differs considerably 

 from the normal liquid. The fatty globules 

 contained in it vary greatly in size, often 

 being very large, and existing within isolated 

 or aggregated epithelial cells, some of them 

 resembling exudation-corpuscles. 



