MAMMARY GLANDS. 



MAN. 



. -..; 



The lacteal gland in it* development follow, the same course u 

 UM other cutaneous glands, and i, according to I-angcr, originally 

 nothing but *oli<l papillary projection of the mucous Uycr of 

 UM e|*lrrmi.. which U inverted by a layer of denser dermal 

 tusoe. In UM aixUi to UM MTtnth month it throw* out a certain 

 Dumber of bud*, and in this way aruw the Brut rudiment* of the 

 mhetquent lobe*. TbtM arr, at first, nothing but minute pyri- 

 form or Baak-ahaped propane* of the common rudiment of the 

 gland, which do not separate from each other until towards the 

 cod of forta! life, at which time they open externally; whilst at the 

 nine time rounded or elongated buds begin to appear at their end*, 

 which at thi* time are also aolid. At the period of birth the gland 

 measure* from 14'" 4", and already distinctly exhibit* a certain 

 number (IS IS) of divisions, of which the internal still approximate. 

 The rudimentary papilla* in fact have either simple flask-like rude, or 

 terminate in two or three sinuoaitie* ; whilst the others are in con- 

 nection with a greater number. The excretory duct of each of these 

 rudimentary lobule*, which i* either simple or possesses two or three 

 branches, i* composed of a 6l>rous membrane of immature nucleated 

 conuectire tiaaue, and an epithelium of small cylindrical cells, and ia 

 manifestly hollow ; whilst the dilated ends, which cannot in this cose, 

 any more than in other glands in the process of development, at this 

 time be termed terminal vesicle*, are still solid ; being wholly com- 

 posed, beaidea the fibrous tunic continued upon them, from the ducU 

 of minute nucleated cell*. From this very simple form the latter one 

 U thus developed ; by the long-continued germination of the primary 

 and subsequently-formed clavate ends, and their simultaneous.exca- 

 ration, a much-branched duct, beset in iU onsets with whole groups 

 of hollow gland-vesicles, is at last formed. 



At the commencement of pregnancy the mammary glnnd, which up 

 to the period of puberty had been but little developed, enlarge* ; its 

 increaM of ize keep* pace with the progress of gestation, and before 

 it* termination a thin serous milky fluid begins to be secreted. 

 Directly after parturition the quantity of milk increases, and it 

 become* more thick and rich, combining in itself all the best prin- 

 ciple* for the nourishment of the young animal. It continues to 

 flow for a length of time proportioned to the age at which the 

 young animal can >eek its own food, and then gradually sub- 

 aiding, the gland decreases to the came size which it hod before 



The Milk, the secretion of the mammary glands, consists of a fluid, 

 the milk-plasma, and innumerable spherical opaque corpuscles, with 

 the brilliant aspect of fat-drops suspended in it These corpuscle* 

 the milk-globules vary in size from immeasurable minuteness up to 

 0-001"' 0-002'", and more, and most probably do not consist of the 

 fatty part of the milk alone, but have aim a delicate investment of 

 casein, and it i* to them that the whiteness of the milk is owing. 

 Will. re*pect to the formation of the milk, it i* to be remarked that, 

 except at the periods of lactation and pregnancy, the glands contain 

 nothing but a small quantity of yellowish viscid mucous, with a certain 

 number of epithelial cells, and arc lined up to their extremities by an 

 epithelium, which in that situation i* teaselated, but externally is more 

 cylindrical. With conception this state of things is altered. The cells 

 of the gland-vesicles begin to develop, at first a little, and subse- 

 quently more and more fatty matter within them, and to enlarge, so 

 a* to fill the terminal vesicle*. To this is added, before the end of 

 pregnancy, a new formation of fat, containing cells in them, by which 

 UM older cells are forced into lactiferous ducts, which they gradually 

 fill. Thus it happen*, that although a true secretion is not at that 

 time set up, (till in the latter half of pregnancy a few drop* of fluid 

 may be expressed from the gland, which, a* is shown by it* yellow 

 colour, i* not milk, but nevertheless contain* a certain number of fat- 

 giobulc* from UM more or les* disintegrated fatty cells, exactly resem- 

 bling UM subsequent milk-globule*, and also contain* such cell* either 

 with or without a tunic, UM so-termed colostrum corpuscle*. On the 

 commencement of lactation after parturition the cell-formation iu the 

 gland-VMtcle* proceed* with exceaaive energy, in consequence of which 

 UM accretion collected in the lactiferous duct* and glaud-veiicle* i 

 evacuated a* UM colostrum or immature milk, the true milk taking 

 it* place. The Utter in the extremities of the gland consist* only of 

 some fluid and cells entirely filled with fat-globulw, which sometimes 

 occupy UM gland-veaicle* alone, sometime* associated with pale 

 epithelial cells, which however always contain more or lea* fat, and' 

 originate either in a free* cell-formation or from epithelial cells, in a 

 way analogous to tl.at in which the cutaneous sebaceous matter is 

 formed, by their continued multiplication. These cell*, which Kiillikcr 

 designate* a* milk-cell*, break up so soon a* they reach the lactr 

 duet* into their element*, the milk-globule*, the membrane, and for 

 UM Boat part al*o the nucleus, disappearing without a vestige being 

 left, eo that the milk when accreted usually present* no indication of 

 it* mode of origin. At most there occur in it a very few larger or 

 smaller aggregation* of milk globule*, which from their similarity to 

 thoce met with in the colostrum may likewise be termed colostrum 

 eorpoKles. The secretion cf the milk therefore depend* essentially 

 upon a formation of fluid and fat containing cells in the gland-vesicle*, 

 aod consequently falls into the category of those secretions into the 

 competition of which morphological element* enter ; above all to the 

 fatty, secretions, such u the cutaneous sebaceous matter, in which cells 



of a precisely similar kind occur to those met with in the glsml-vcaiclc* 

 of the lacteal gland* and in the colostrum. 



( KI. Hiker, Manual of Human Hittology.) 



MAMMKA, a genus of Plants belonging to the natural order 

 liutlifinr. It has two deciduous equal sepals ; 4 or 6 petal*, coriaceous, 

 somewhat equal, and deciduous; stamens distinct, or slightly united 

 at the base, indefinite, deciduous ; filaments short ; anthers adnate, 

 2-celled, opening longitudinally ; ovary 4-celled ; ovule solitary, erect ; 

 style short; itipma 4-lobed, with emarginate lobes ; fruit pointed by 

 the remain* of the style, with a hard put&inen and fleshy rind ; 4- or 

 by abortion 2- or 3 celled ; seeds thick and large. 



M. Atntricana, or the American Mammee-tree, the only species of 

 this genus, forms a handsome tree with a spreading elegant head, 

 which is compared with that of a Magnolia. The Sower* are odorifer- 

 ous, and employed as an aromatic addition to liqueurs called Eau and 

 Crfiine des Creole* in some of the West India Islands. The fruit i* 

 large and ho* a double rind, of which the outer is thick and leathery ; 

 the inner one is thin and bitter, and contain* the pulp closely adher- 

 ing to it, which is of a yellow apricot-colour, whence it it sometimes 

 called Abricot de Saint Domingue. This pulp ha* a pleasant but 

 peculiar taste with an aromatic smell ; it may be eaten raw, or cut 

 in slices, with wine or sugar ; or cooked, which deprive* it of its 

 gummy portion. It U also preserved in wine sweetened with sugar, 

 or iu brandy. (Labat) The fruit is considered nourishing and 

 pectoral, and is much esteemed in America. The bark abounds in a 

 strong resinous gum, used by the negroes for extracting chigoes from 

 their I'eet. A bath of the bark renders the sole* of the feet like 

 Mangrove bark. Attempt* have been made to cultivate it in stove* 

 iu this country. According to Sweet, it grows freely in sandy loam ; 

 and ripened cuttings, with the leaves not shortened, root in sand under 

 a hand-glass in heat. 



MAMMKLLI'PORA. Bronn proposes thi* name instead of Lymno- 

 rea, Lam., for a genus of Fossil Zoophyta, analogous to Alcyoniuia. 

 [LYMNOHEA.] 



MAMMOTH, a term employed to designate the Fossil Elephant*. 

 The name has been erroneously applied sometimes to the Mastodon. 



[Er.KI'HANT.] 



.MAX, the highest being in the animal series. Although attempts 

 have been often mode to establish a close affinity between man and 

 the highest forma of Mammalia, the most recent writer* on the 

 structure of the higher forms of animals are inclined to place him 

 not only as a species and genus distinct from all other?, but as occupy- 

 ing a position of ordinal value. Thus Professor Owen nays, " Man is 

 the sole specie* of his genus, the sole representative of his order." 



The study of man may be pursued under three different beads. 

 Thus we may examine the structure of the organ* of his body nnd 

 the functions they perform, and this constitutes the sciences of Human 

 Anatomy and Physiology. We may also compare his structure with 

 that of the lower animals from a zoological point of view, using our 

 anatomical and physiological knowledge for this purpose. This is 

 called the science of Anthropology. In the third place we may study 

 him in his relations to himself, and consider the varieties he presents. 

 This constitute* the science of Ethnology. All these departments of 

 science are contemplated in the natural history of man. 



In this work the anatomy and physiology of man are treated under 

 the various separate heads of the organs and functions of man. In the 

 present article we address ourselves to the principal features of the 

 sciences of Anthropology and Ethnology. The following apothegms 

 by Dr. Robert Gordon Latham, to whom the science of ethnology 

 i* .deeply indebted, will present to the reader a view of the object 

 and range of these science* : 



1. The natural history of man is chiefly divided between, two sub- 

 jects Anthropology and Ethnology. 



2. Anthropology determines the relations of man to the other 

 iliimmalia. 



3. Ethnology the relations of the different varieties of mankind 

 to each other. 



4. Anthropology is more immediately connected with zoology ; 

 ethnology with history. 



5. Whilst history represents the actions of men as determined by 

 moral, ethnology ascertains the effects of physical influences. 



(i. History collects it* facts from testimony, and ethnology doe* 

 the same; but ethnology dealt with problems upon which history 

 is -ili-iit, by arguing backwards, from effect to cause. 



1. This throws the arena of the ethnologist into an earlier 

 period of the world's history than that of the proper historian. 



8. It is the method of arguing from effect to cause which 

 gives to ethnology its scientific in opposition to its literary aspect ; 

 placing it, thereby, in the same category with geology, as a pattoon- 

 tological science. Hence it is the science of a method a method by 

 which inference does the work of testimony. Furthermore, ethnology 

 is history in respect to its results ; geology in respect to its method. 

 And in the same way that geology has it* zoological, physiological, 

 and such other aspects as constitute it a mixed science, ethnology has 

 them also. 



9. The chief ethnological problems are those connected with 

 1, the unity; 2, the geographical origin; 3, the antiquity; 4, the 

 future destination upon earth of man. 



