ON TUBIFEX mVULORUM. 165 



affecting the udder of the cow, male animals not being affected by 

 it ; and that since small-pox has so much decreased in the rural 

 districts, Cow-pox is almost extinct, raises a strong presumption 

 that it was produced by inoculation from the hands of convalescent 

 patients. 



I must now bring this long paper to a conclusion. My limits 

 are exhausted, but not my subject. No branch of science has, in 

 the words of Charles Kingsley, " helped so much to sweep away 

 that sensuous idolatry of mere size, which tempts man to admire 

 and respect objects in proportion to the number of feet or inches 

 which they occupy in space " ; and the study has shown us how 

 these minute organisms have, perhaps, had more important rela- 

 tions in reference to the existence of life on our globe than the 

 vast denizens of our primeval forests, or even the gigantic Saurians 

 of previous geologic epochs. 



®u ^ubifcy IRivulorum. 



By a. Hammond. F.L.S. 



Second Paper.* 



Plates ;^^ and 34. 



THE reproductive system of Tubifex presents many points of 

 interest, enhanced perhaps by their obscurity and the dif- 

 ferent opinions that have been advanced concerning them. 

 I will give, therefore, a resume of Claparede's observations, adding 

 the views of Lankester, which appear in some cases diametrically 

 opposed thereto, and such remarks of my own as the occasion 

 may seem to warrant. 



I may say, in the first place, that these worms are hermaphro- 

 dite, uniting both sexes in one individual; but, as generally 

 happens, the congress of two individuals is necessary for the 

 completion of the reproductive cycle. Each worm, therefore, 



* For First Paper, see Vol. 1. of this Journal, p. 14. 



