EFFECT OF CONJUGATION 357 



the difference is very slight. In no case did the conjiigants 

 have a higher rate of fission, although in Experiments 4, 7, 8, 

 12 and 14 the difference between conjugants and non-conjugants 

 was so small as to be without significance. But in the majority 

 of the experiments, and particularly those which included many 

 cases and were jittle disturbed by extrinsic factors, those that had 

 not conjugated showed a fission rate higher in a marked degree. 

 And this higher fission rate of the non-conjugants persisted for 

 weeks and months (see the results of Experiments 1, 2 and 6). 



So much has been said of the greater reproductive power, the 

 ''active cell prohferation," et cetera, of the period following con- 

 jugation, that this result appears surprising. Yet those inves- 

 tigators who have examined the matter with the greatest care, 

 came long ago to the same result. Maupas insists again and 

 again, at great length, in opposition to the prevailing views, that 

 conjugation does not increase the rate of reproduction. Since 

 the matter is an important one, and one on which incorrect ideas 

 are prevalent, and since Maupas had evidently done much careful 

 work on the question, it niay be worth while to give a resume of 

 the points he makes. The following passage might well be 

 designed as a statement of the present condition of affairs: 



On a afiirme que la faculte fissipare des Cilies etait modifiee par la 

 conjugaison, et que cet acte sexuel avait, pour principal effet, de la 

 renforcer et de I'accelerer. Les Cilies, au sortir de la conjugaison, se 

 multiplieraient beaucoup plus rapidement qu'ils ne le font plus tard. 

 Cette opinion est devenue courante, et on la trouve reprocluite dans 

 les Memoires et les Traites Generaux, comme une verite definitivement 

 acquise. Elle a ete emise i)our la premiere fois, par Biitschli en 1876, 

 et reprise ensuite par Balbiani, en 1882, qui s'en est empare, et a 

 meme cru en avoir fourni la demonstration experimentale ('88, pages 

 254-255). 



Maupas then examines the supposed evidence of Biitschli and 

 Balbiani, showing that it amounts to nothing. He sets forth that 

 in his own records of fissions, beginning in a number of cases with 

 ex-con jugants, there is no indication of a greater rate of fission 

 in the early part of the cycle. He says of the fissions: 



Elles se succedent avec une marche uniforme, modifiee uniquement 

 par les variations de temperature. Je ne me suis i)as contente de cette 



