Descriptive catalogue of the teratological series in the museum of the Royal College of Surgeons of England / [by] Benjamin Thomson Lowne.

  • Benjamin Thompson Lowne
Date:
1872
Catalogue details

Licence: Public Domain Mark

Credit: Descriptive catalogue of the teratological series in the museum of the Royal College of Surgeons of England / [by] Benjamin Thomson Lowne. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

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    The fusion of distinct buds in plants, as in syncarpy (Prep. Nos. 6 to 14), is clearly a condition analogous to the union of embryos originating on a single yelk : in both cases the united growths probably originate by a similar process, the formation of two centres of growth in the place of one. A similar mode of union occurs normally between contiguous zooids in the Gorgonidae, or fan corals. In the eggs of birds three distinct conditions occur:— First, there may be two yelks enclosed in a single shell; this condition may give rise to two young, and if they become united they only adhere by heterologous parts, or possibly by the integument of the umbilicus *. Se- condly, there may be two cicatrices on one yelk : in this case the yelk is virtually equivalent to two mammalian yelks, as the cicatrix is the homologue of the mammalian yelk, the great food-yelk being absent in this Class f. Or, thirdly, two embryos may be formed on the same cicatrix: this condition is the most frequent, and gives rise either to twin chicks (?) or to double monsters. Dichotomy, as already stated, very rarely affects a limb or digit; it is liable to occur in the kidneys. Doubling of the cavities of the heart, bladder, and uterus are malformations totally unlike those arising from dicho- tomy. The latter organ is certainly doubled by arrest of development. Classes III. & IV. Arrest and Excess op Groavth Include, first, dwarfs and giants, which are either the effect of variation of nutrition or development; and, secondly, cases of partial excess or arrest, which are more nearly allied to ordinary disease: these may be considered as cases of intra-uterine hypertrophy or atrophy. * Thoro is no improbability in such union, and it appears to have been observed. M. Caruille Daroste thinks this adhesion occurs. t E. van Bonedcn, ' Ileehcrchcs sur la composition et la significa- tion de l'ceuf'.' Bruxcllcs, 1870.