332 The Ohio Naturalist. [Vol. V, No. 7, 



that the cell wall was developed as a protective covering. When 

 these primitive cells were in process of division there could be an 

 interchange of food from the one to the other so long as the 

 protoplasmic connection was not completely cut. After complete 

 separation the two daughter cells, still lying in contact, could 

 exchange food by osmosis, the one having a less amount of food 

 taking from the one having a greater supply. After the two cells 

 had separated they might exchange food in the same way on 

 coming in contact for any length of time by accident. In this 

 way sexual evolution may have had its beginning as well as 

 parasitism in all of its forms. After the process of temporary or 

 permanent conjugation was once established it would be of 

 advantage to the species under many adverse conditions. A 

 set of starved or weak organisms meeting with a well nourished 

 lot could conjugate either temporarily or permanently, greatly 

 to their advantage, without doing the stronger individuals any 

 special harm. Such is apparently the behavior of various lower 

 organisms at the present time. Furthermore a swarm of uni- 

 cellular organisms or zoospores in a given area is, by conjuga- 

 tion, reduced to just half the previous number. The mere 

 reduction in the number of units might be a very important fac- 

 tor in the immedi.ate welfare of the species especially when the 

 further delay of reproduction incident to the process of conjuga- 

 tion is taken into account. In many of the lower plants the 

 arrival of adverse conditions is the stimulus to the formation of 

 resting zygospores or oo.spores by means of which the organism 

 is preserved until a more favorable environment is again at hand. 

 Rejuvenescence, using the term in its broadest sense seems at 

 least a very plausible cause of the origin of sexuality if it is once 

 admitted that conjugation is not one o.' the fundamental prop- 

 erties of the protoplasm of primordial organisms. Other means 

 of rejuvenescence should serve the same purpose as the stimulus 

 and reaction which one mass of protoplasm must exert on 

 another during conjugation, leaving out of consideration the fact 

 of the reduced space occupied by the two united organisms and 

 consequently the less surface in contact with the surrounding 

 medium. A tree may be rejuvenated by placing a fertilizer 

 al:)Out its roots. So organisms which naturally rejuvenate only 

 through conjugation may be rejuvenated through a favorable 

 change of food or other factors of environment, thus actually 

 delaying the necessity of a conjugation for a long period of time. 

 Whether conjugation was long or short in its evolution is of 

 no special importance in the discussion of the remaining ques- 

 tions formulated above. The first time that nucleated cells con- 

 jugated so completely as to act in cell division as a single cell a 

 disturbance was present not operative in the race previously. 

 The two nuclei having fused contained twice the amount of 



