72 The Presidenfs Address. 



plirodite creature, wliich in its progress towards a reciprocal 

 sexvial maturity yet carries on self-impregnation, so that, at 

 the death of its host, and thus wiihin a moderate time of its 

 own death, impregnated ova may be set free to again become, 

 perhaps, Monostoma embryos to pass through a Cercarial 

 stage, or the lowest phase of a Trematode life " (Q. J. M. S., 

 Oct., 1867, p. 94). Dr. Maddox thinks it possible that the 

 earliest stage of the parasites may be passed in the bodies of 

 shell-fish, Avhich the haddock eats. 



In March, Mr. "Whitney brought before us a series of re- 

 markably interesting researches in a paper " On the Changes 

 which accompany the Metamorphosis of the Tadpole, in re- 

 ference especially to the Respiratory and Sanguiniferous 

 Systems ;" and those Avho had the pleasure of hearing this 

 paper read will remember the beautiful series of coloured 

 drawings and anatomical proportions with which it was 

 illustrated. 



Mr. Whitney explained the nature of the two sets of gills, 

 one external and the other internal, with which the tadpole 

 is furnished. He showed the way in which the respiratory 

 function is transferred from the outer to the inner gills ; the 

 development of the latter taking place in proportion to the 

 atrophy experienced by the former. 



After showing, stage by stage and step by step, the de- 

 velopment and the changes which take place in these two 

 sets of gills, Mr. Whitney described the true lungs which 

 co-exist with the gills of the tadpole in an incipient form, 

 and pass through their gradations of development simul- 

 taneously with those phases of maturity, decline, and decay 

 exhibited by the gill organs. To see the action of the inner 

 gills in a living tadpole, Mr. Whitney applies a single drop 

 of chloroform to render the creature insensible, and then 

 carefully cuts aw^ay the integument with fine scissors, thus 

 laying the gills bare, while the circvilation is vigorous, and 

 capable of affording a splendid sjDcctacle on the stage of the 

 microscope. 



In May we were indebted to Dr. Lionel Beale for a paper 

 on '^ Nutrition exhibiting many facts of the highest im- 

 portance, arrived at by Microscojiic Investigation, and con- 

 troverting opinions expressed by Mr. Herbert Spencer and 

 other well-known writers on Biological Subjects concerning 

 so-called ' Vital Action Processes.' " Dr. Beale, as my 

 hearers are well aw^are, divides the matter contained in living 

 bodies into three classes — germinal matter, formed material, 

 and pabulum. The first only he considers alive, or possessed 

 of vital properties. The formed material he regards as no 



