1832.] A CURIOUS EXPERIMENT. 39 



Planariae in different parts of the southern hemisphere.^ 

 Some specimens which I obtained at Van Diemen's Land, 

 I kept alive for nearly two months, feeding them on rotten 

 wood. Having cut one of them transversely into two nearly 

 equal parts, in the course of a fortnight both had the shape 

 of perfect animals. I had, however, so divided the body, 

 that one of the halves contained both the inferior orifices, 

 and the other, in consequence, none. In the course of 

 twenty-five days from the operation, the more perfect half 

 could not have been distinguished from any other specimen. 

 The other had increased much in size ; and towards its 

 posterior end, a clear space was formed in the paren- 

 chymatous mass, in which a rudimentary cup-shaped mouth 

 could clearly be distinguished ; on the other surface, 

 however, no corresponding slit was yet open. If the 

 increased heat of the weather, as we approached the equator, 

 had not destroyed all the individuals, there can be no doubt 

 that this last step would have completed its structure. 

 Although so well-known an experiment, it was interesting 

 to watch the gradual production of every essential organ, 

 out of the simple extremity of another animal. It is 

 extremely difficult to preserve these Planariaj ; as soon as 

 the cessation of life allows the ordinary laws of change to 

 act, their entire bodies become soft and fluid, with a rapidity 

 which I have never seen equalled. 



I first visited the forest in which these Planariae were 

 found, in company with an old Portuguese priest, who took 

 me out to hunt with him. The sport consisted in turning 

 into the cover a few dogs, and then patiently waiting to fire 

 at any animal which might appear. We were accompanied 

 by the son of a neighbouring farmer — a good specimen of a 

 wild Brazilian youth. He was dressed in a tattered old 

 shirt and trousers, and had his head uncovered : he carried 

 an old-fashioned gun and a large knife. The habit of 

 carrying the knife is universal ; and in traversing a thick 

 wood it is almost necessary, on account of the creeping 

 plants. The frequent occurrence of murder may be partly 

 attributed to this habit. The Brazilians are so dexterous 

 with the knife, that they can throw it to some distance with 

 precision, and with sufficient force to cause a fatal wound. 

 1 have seen a number of little boys practising this art as a 

 game of play, and from their SKill in hitting an upright 



* I have described and named thf!«e ipecics in the "AnnaU of Natursi 

 Hiatory," vol. xiv., p. 041. 



