Regeneration in Animals.

Otago Witness, Issue 2686, 6 September 1905, Page 76

Regeneration in Animals.

Among the- most vital power* of adaptation is the power some animals possess of maintaining their cornoraal entity under dimculties by replacing parts of the body

that may be last by accident ; this pciver of renewal ox'stin*, in come cases, even, to the extent of producing a new head when, v* frequently happens ir these lower walks of life, tho animal has ]-een deprived of that organ by bollig-ejvnt companions or through, fee me unavoidable contingency. Seven original article^ on regeneration *in various animals are presented in the la^t i umber of the Arcb.iv fur Enlv.ickluugsrnechaaijk der Orgamsmen"' (Le-ipsie), edited by tiie noted experimental biologist, Wilhclm Roux. In order to study the pover of regeneration iv the crayfish, a large number of specimens were deprived of one leg and left for a couple of months to see .f the appendage would be replaced. In a few of the cravssh the appendage did not grow again; m others, a new one grew, perfecfe m form, but smaller, and several regenerated a perfectly normal leg, having tiie usual number of joints, with pincers at the. cno, a s well as lli-o gill wluoh is attached to Ilie ies- :n ihe crayfi«h. Snails, aiso, are able to replace lost paris to a Certain degree. The soft tentacles on the head, whi^h may be extended or chawa in. and carryorgans of special sense, are regenerated', with their tense organs, in a short time <--fier boinj cut off. " Experiments made on various hmde of amphibian larva? c?\o evidence against tho theory held by "Woisir.vin and others tha£fche regenerative power of an or«?an Spends cv Ws relative Importance and Jts exDosttro Io injury or danger of being lost" and Bi-'T.vrd that ncithrr on 3 plays any role in. Lhs renewal of tbe organ, but thai the imuurtant factors are the degree of differonI'atfon of the organ — whether the animal hae reae'.ie .1 ♦matuvty o-r not. and whether, it belongs to a highly specialised type. On the tiie re are curative power seems io depend en the general degree of development. Ir- the amphibia, the ppwer of rei:ewin<- an organ 's 104 at the time o£ ehanamg from the lanal to the adult form.-