358 



PKOVISIONAL HYPOTHESIS 



Chap. XXVII. 



Pangenesis, which imp! 



that 



whole 



'g 



of every separate atom or unit, reproduces itself. Hence 



ovules and pollen-g 



buds 



the fertilised seed or egg, as well 



— include and consist of a multitude of germs thrown off 



from each separate atom of the organism 



In the First Part I will 



enumer 



as briefly as I 



the 



groups of facts which seem to demand connection ; but 



subjects 



hitherto discussed, must be treated at dispropor 



and 



length. In the Second Part the hypothesis will be g 



we shall 



assumpt 



♦after considering how far the necessary 

 themselves improbable, whether it serves to 



bring under a single point of view the various facts 





Paet I. 



Reproduction may be divided into two main classes, namely, 



effected in many ways — by 



xual and 



The 



kinds 



gemmation, that is by the formation of buds of 

 and by fissiparous generation, that is by spontaneous or artificial 

 division. It is notorious that some of the lower animals, when 

 cut into many pieces, reproduce so many perfect individuals: 

 Lyonnet cut a Nais or freshwater worm into nearly forty pieces, 

 and these all reproduced perfect animals. 1 It is probable that 



gmentation could be 



ied much further in some of 



protozoa, and with some of 



reproduce the parent-form, 

 there was 



he lowest plants each cell will 

 Johannes Miiller thought that 



an important distinction between gemmation and 



fission; for in the latter case the divided 



por 



small, is more perfectly organised ; but most physiolog 



however 



convinced that the two processes are 



Prof. Huxley remarks, "fission 



tially alike 



2 



(I 



little more than a peculiar 



mode of budding," and Prof. H. J. Clark, who has especially 



1 Quoted by Paget, 'Lectures on 

 Pathology/ 1853, p. 159. 



( 



2 Dr. Lachmann, also, observes 



2nd series, vol. xix 



1857, p. 231) 



with respect to infusoria, that "fissa- 

 "tion and gemmation pass into each 

 "other almost imperceptibly." Again, 



W. C. Minor ( 



328) 



shows that with Annelids the distinc- 

 tion that has been made between fission 

 and budding is not a fundamental one. 

 See Bonnet, ' CEuvres d'Hist. Nat.,' torn, 

 v., 1781, p. 339, for remarks on the 

 budding-out of the amputated limbs 

 of Salamanders. See, also, Professor 

 Clark's work « Mind in Nature,' New 

 York, 1865, pp. 62, 94. 



