president's addkess. 221 



ever inspired by cytulogical investigation of the egg of a single animal ; 

 and in the researches of Earfurth,^ which so far revolutionized 

 our knowledge of the so-called ' liver ' of the invertcbrata as to 

 early necessitate the abolition of that term, Arion and Helix rank 

 foremost. 



Claiming, on your behalf, a leading consideration for the MoUusca 

 in questions cytological, allow me to remind you of the interest 

 attaching to the work of Ivofoid and Castle, which I brought under 

 your notice last year. It has been followed by an elaborate inves- 

 tigation into the cell-lineage of Limax maximus, by Meisenheimer,* 

 while rfliicke would appear to be contemplating work with the 

 moUuscan nerve-cell.^ Von Lenhossek has given us a study of the 

 Cephalopod optic lobe and retina,* which for masterly treatment has 

 never been surpassed. It suggests that in comparative histology 

 the molluscan eye will play a role no less important than it has 

 in anatomy in the hands of Grenacher, and in controversy in those 

 of Huxley and Mivart. 



In purely experimental cytology, Fujita has made some interesting 

 observations upon the egg Aphjsia, which appear to show ^ that 

 its derivative embryo-cells may overcome the efforts of mutilation ; 

 and Crampton, dealing with llyanassa ohsoleta, has for the first time 

 succeeded in making an extended experimental study ^ of isolated 

 blastomeres, which is full of interest. 



Platner has already done excellent work with the molluscan 

 nucleus; and, during the year, Auerbaeh,' De Bruyne,* Kostanecki 

 and Wicrzejski,^ Bolles-Lee,'° and McMurrich," dealing with the 

 ' astrosphere ' and ' centrosome,' have involved Fulgur, Helix, 

 Paludina, and Fhysa in what future historians will probably 

 record as one of the most remarkable biological conti'oversies of 

 our time. 



With advance of knowledge, the appearances expressed in the 

 beforementioned terms have been held indicative of the existence of a 

 supposed organ of the cell, equal almost in rank with the nucleus ; and 

 Ko.-^taiiecki and Wierzejski (^following Boveri, who attributed to the 

 ' centrosome ' the initiation of divisional activity) in lately studying 

 Phyaa have gone further, and argued that the stimulus to division of 

 the developing egg-cell depends mainly on the protoplasm and contro- 

 somes, which they regard as physiologically complementary. 



Excitement concerning these structures reached its highest pitch in 



1 D. Barfurth, Arch. Mikr. Anat., Bd. xxii, p. 473. 

 ^ J. Meisenlieimer, Zeit. Wiss. Zool., Bd. Ixii, p. 415. 

 3 Max Prtiicke, op. cit., Bd. Ix, p. 500. 



* M. voii Lenho.ssek, Arch. Mikr. Auat., Bd. xlvii, p. 45. 

 6 J. Fujita, Zool. Mag. Tokyo, vol. viii, p. 47. 



* H. E. Crampton, Arch. Eutwick. Mech., Bd. iii, p. 1. 

 ■' L. Auerbach, Jeuaische Zeitscli., Bd. xxx, p. 405. 



* C. de Bruyne, Bull. Acad. Beige, ser. Ill, vol. Ivi, p. 211. 



* K. von Kostanecki and A. Wierzejski, Arch. Mikr. Auat., BJ. xlvii, p. 309. 

 10 A. Bolles-Lee, " La Cellule," torn, xi, p. 225. 



'1 J. P. McMurrich, Anat. Anz., Bd. xii, p. 5a4. 



