The American text-book of operative dentistry / In contributions of eminent authorities. Ed. by Edward C. Kirk.

  • Edward Cameron Kirk
Date:
1900
Catalogue details

Licence: Public Domain Mark

Credit: The American text-book of operative dentistry / In contributions of eminent authorities. Ed. by Edward C. Kirk. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

    61/864 (page 59)
    haps by the action of too powerful reagents, which led Goodsir and his followers to describe the appearance of an open groove. The Goodsir theory had no foundation in fact, because no such open groove ever existed in that situation. The various foldings found in embryonic tissue no doubt are an ex- pression of an economic provision on the part of Nature in caring for Fig. 40. Section of jaw, embryo of sheep, showins; sr.iwth of enamel orc^an and dentin germ: 1, large mass of epithelium ; '1, enamel organ ; 3, dentin germ ; 4, growing jaw. the tissue that is to be taken up by the expansion of the parts during its growth, as eventually they are all smoothed out. Rose's models^ show that the original inflection (stratum Malpighii) at an early stage divides into two portions, one of which, the outer, is nearly perpen- dicular and is intimately connected with the formation of the lip furrow, whilst that immcHliately under consideration passes almost horizontally backward into the tissue beneath. At about the forty-eighth day, from the lingual side of this groove, at a point where a tooth is to be formed, a portion of the stratum Malpighii is found growing into the embryonic connective tissue, in ^ Models of Developing] Teeth and Jaws. By Carl Rose, M. D.