A study of the differentiation of tissues in the regenerating crustacean limb / by Victor E. Emmel.

  • Emmel, Victor E. (Victor Emanuel), 1878-1928.
Date:
1910
Catalogue details

Licence: In copyright

Credit: A study of the differentiation of tissues in the regenerating crustacean limb / by Victor E. Emmel. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    Ill progress of the present work. I am also indebted to Professor A. D. Mead, of Brown iTniversitj, for generously permitting me the iise of materials and apparatus at the Experiment Station of the Ehode Island Commission of Inland Fisheries; and to Professor E. J. Terry, of Washington University, for valuable suggestions during the completion of the present paper. II. Material and Methods. A serious obstacle encountered in determining the origin and dif- ferentiation of a regenerating tissue is the difficulty of securing a complete series of successive developmental stages. If a number of animals are operated upon at the same time and material fixed at successive intervals, it is usually found necessary in subsequent study to make an extensive rearrangement of the material on account of variations in size and rate of growth. These technical difficulties were considerably lessened in the present work because of the excel- lent material obtained at the lobster hatchery of the State Experiment Station at Wickford, Ehode Island. From a hatchery pool contain- ing several thousand lobster fiy, it was possible to select a large number of animals which were practically equal in age and size, and which had all moulted to the same stage within less than twenty- foiir hours. This last point is of considerable importance, since It had been ascertained in previous experiments (’06) that the age of the^ animal and the time, in relation to moulting, at which the operation is made are important factors influencing the rate of regen- eration. These young lobsters were also further favorable for study because the exoskeleton had not as yet attained such an amount of chitin and lime salts as to necessitate decalcification before sectioning. he operation consisted in the autotomous removal of both chel* The lobsters, about 300 in number and all practically equal in age and size, were placed in floating cars and kept in as nearly normal condition as possible. Specimens were then preserved at two, four and eight hour intervals throughout a period of fourteen days, in w 1C time the chelae had undergone complete regeneration. From this succession of stages about 54 were selected, sections of the chel® were cut 5 micra in thickness and mounted in series. In order to