In an attempt to replicate the findings reported in this Journal by Weyant and Smith (1987), members or recent donors to a Canadian civil liberties organization were asked to donate money under one of three conditions: (a) In the control condition, they were simply asked for a donation; (b) in the “smaller request” condition, they were asked to make a donation, but amounts of Canadian $30 to $100 were suggested; and (c) in the “larger request” condition, amounts of $50 to $250 were suggested. Unlike the Weyant and Smith studies, we found no difference in the proportion of respondents making a donation, but significant differences in the size of the donations made by those making donations. In our study, the most effective way of getting large donations was to ask for a large amount. It was suggested that the most likely explanations for the differences in the results of the two studies were the following: First, our target population were previous donors to the organization, whereas those in the Weyant and Smith studies were not likely to have been. Previous research suggests that those who had been donors previously are influenced, positively, by requests for a specific large donation, whereas those not previously approached are, if anything, negatively influenced. Second, our “larger request” appears to be within a plausible range for donations, whereas the larger request in the Weyant and Smith study may have been seen as being outside of the plausible range. In any case, however, we would recommend caution in drawing a conclusion about the most effective request size to encourage people to donate money to charity.

Left forelimbs of postmetamorphic Xenopus laevis froglets were repeatedly denervated prior to and following amputation. Amputations were performed 14, 21, 28, or 42 days after the original denervation. A tissue-regenerative response resulting in the formation of a spike-shaped, heteromorphic outgrowth was found in the sham-denervated and control animals, but dedifferentiation of the stump tissues was not apparent. Tissue-regenerative outgrowths were not observed in the denervated cases; instead, dermal wound healing and stump and scar formation occurred. In both control and experimental cases, however, a periosteal proliferative response to amputation injury led to the development of a greatly thickened periosteum the length of the amputated radius-ulna as well as a cap of cartilage at the distal end of these bones. We conclude from these results that forelimbs of postmetamorphic froglets are incapable of adjusting to a prolonged nerveless state sufficient to allow the normal tissue-regenerative response of spike outgrowth formation.

In vitro experiments were carried out to determine the effects of prolactin, and prolactin in combination with other hormones on the regeneration of adult newt tail blastemata. A total of 271 blastemata were explanted 13 days postamputation and were organ cultured for 96 h at 20 (±1)°C. Treatment with prolactin alone resulted in an increase in the blastema cell density of the tail regenerates. Cell accumulation and cell alignment were observed ventral to the reconstituted spinal cord. Prolactin and thyroxine, in combination, improved development of tail regenerates as compared with treatment with prolactin or thyroxine singly, supporting the results of earlier in vivo studies. Optimal development was obtained only when prolactin, insulin, thyroxine and hydrocortisone were added to the culture medium. Regeneration of tail explants maintained in medium augmented with the four hormones closely resembles that of in vivo tail blastemata 17 days post-amputation.