On regeneration in the pigmented skin of the frog, and on the character of the chromatophores / by Leo Loeb and R.M. Strong.

  • Loeb, Leo, 1869-1959.
Date:
[1904]
Catalogue details

Licence: In copyright

Credit: On regeneration in the pigmented skin of the frog, and on the character of the chromatophores / by Leo Loeb and R.M. Strong. 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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    The solution and the tap water for all these series were changed every day for the first week and every other day thereafter. At the end of periods varying from ten hours to five weeks, frogs were killed and the tissue about the wounds removed. Corrosive-acetic was used for fixing and the material was embedded in celloidin. Serial sections were made and stained in Delafield’s hsema- toxylin and eosin. Altogether, series of sections from 62 frogs were examined.1 Observations.—Xo constant effects on regeneration have been noticed for the atropine and pilocarpine solutions used. Regeneration of both epithelium and connective tissue seemed to take place equally well in either the weaker atropine, the pilocarpine solutions, or the tap water. There was no marked difference in the number of mitoses when these solutions were used. In some cases there was a little evidence of pos- sibly greater activity in regeneration, for some cases, in the pilocarpine solution than in the atropine. This difference was very slight and possibly accidental. In one series of experiments the number of leuco- cytes immigrating into the wound was decidedly larger in the pilocarpine solutions. This difference, however, was not observed in a second series. Frogs kept in either the weaker or the stronger solutions of pilocarpine did not behave differently from those in tap water, even at the end of four or five weeks; they were nearly all equally active. The animals placed in the stronger atropine solution were very stupid and helpless at the end of the first day or two, apparently being partially paralyzed, and none lived longer than five days. The weaker solution seemed to have a somewhat similar but much milder effect in a few cases. In the former series of experiments carried out in the spring of 1901, and referred to above, tadpoles, whose tails had been cut, were kept in 1-6 per cent solutions of alcohol and in weak chloroform water up to six days after the operation; the control animals lived in tap wTater. These experiments were undertaken in order to ascertain whether or not these narcotic substances delay and weaken the movements and the growth of the cells. ISTo marked differences in regeneration were ob- served between the different sets of tadpoles, with the possible exception of slight differences in the rapidity with which the epithelium covered the wound. Regeneration of the Epidermis.—Barfurth, 91, observed in the Sala- mander a rapid movement of epithelium over a wound before any in- 1A part of these investigations was carried on with the aid of a grant from the Research Fellowship Fund of McGill University.