VOL. XLII.] PHILOSOPHICAL TRANSACTIONS. GlJ 



manv heads, and one tail. He afterwards at once cut off the 7 heads of this 

 new hydra : seven others grew again ; and the lieads, that were cut off", became 

 each a complete polypus. 



He cut a polypus transversely, into 2 parts : he put these 2 parts close to 

 each other again, and they reunited where they had been cut. The polypus, 

 thus reunited, eat the day after it had undergone this operation : it afterwards 

 grew, and multiplied. 



He took the posterior part of one polypus, and the anterior of another, and 

 brought them to reunite in the same manner as the foregoing : next day, the 

 polypus that resulted, eat : it had continued well 2 months after the operation ; 

 grew, and put forth young ones, from eacli of the parts of which it was formed. 

 The two foregoing experiments do not always succeed ; it often happens, that 

 the 2 parts will not join again. 



To comprehend the following experiment, we should recollect, that the whole 

 body of a polypus forms only one pipe, a sort of gut, or pouch. He has been 

 able to turn that pouch, that body of the polypus, inside-outwards ; as one 

 may turn a stocking. He had several by him, that have remained turned in 

 this manner ; their inside is become their outside, and their outside their inside : 

 they eat, they grow, and they multiply, as if they had never been turned. 



Facts like these, to be admitted, require the most convincing proofs. He 

 asserts he is able to produce such proofs. They arise from the detail of his ex- 

 periments, from the precautions he took to avoid all uncertainties, from the 

 care he used to repeat the same experiment several times, from the assiduity 

 and attention with which he observed them. 



These animals are to be looked for in such ditches where the water is stocked 

 with small insects. Pieces of wood, leaves, aquatic plants, in short, every thing 

 is to be taken out of the water, that is met with at the bottom, or on the sur- 

 face of the water, on the edges, and in the middle of the ditches. What is 

 thus taken out, must be put into a glass of clear water, and these insects, if 

 there are any, will soon discover themselves ; especially if the glass is let stand 

 a little, without moving it ; for thus the insects, which contract themselves 

 when they are first taken out, will again extend themselves when they are at 

 rest, and thus become so much the more remarkable. In order to feed them, 

 we must know how to provide ourselves with insects fit for their food. 



Some Considerations for determining whether Pendulums are disturbed in their 

 Motions by any Centrifugal Force. By the Marquis John Poleni, F.R.S. 

 N° 468, p. 299. From the Latin. 



Sig. Poleiii observes that the method used in discovering the centrifugal force, 



4l 2 



