The President's Address. By the Rev. W. H. Ballinger. 191 



emission, I was enabled to use this apparatus in its simplest 

 condition, and so to ensure less complex results. 



The death-point of the adult was first tested. I found that it 

 was not killed under a temperature of 146" Fahr. This was from 

 4° to 6° higher than any other form I have studied. 



After ten separate tests, carefully worked out, I found that the 

 highest point which the spores or germs could endure, and still 

 germinate, was 190° Fahr. After this point was passed the form 

 never appeared in the closed cell. That is to say, that the spores 

 seen to be deposited in the specially prepared cell, did germinate 

 after being raised to any temperature intermediate between 146" 

 and 190° Fahr., but beyond the temperature of 190° the spore lost 

 its power of germination. 



This is the eighth of these most interesting forms that, either 

 in conjunction with my colleague or alone, I have been able to 

 carefuUy follow through their principal developmental changes. 



It may be well to indicate briefly some of the broader aspects 

 of the study as a whole. 



And first, whether these organisms are animal or vegetable, is 

 without doubt an interesting question. But the more completely 

 we know the organisms the more difficult does the determination of 

 this question become. It may be taken as absolutely certain that, 

 in common with the septic bacteria, they can hve, thrive, and 

 multiply indefinitely in fluids totally devoid of proteinaceous 

 matter, and composed wholly of mineral salts and tartrate of 

 ammonia — as Cohn's nutritive fluid. On the other hand, they are 

 probably even more prohfic in putrefactive animal and vegetable 

 matters. 



But no definite inference can be made from this ; for a form 

 so essentially animal as Paramsecium aurelia, and still more 

 abundantly Stylonychia pustulata, will Hve and rapidly multiply 

 with them in the same simple nitrogenous compounds. 



To argue the vegetal character of these forms from their plant- 

 like abihty to produce protein when supplied only with carbonic 

 acid, ammoniacal salts, some mineral salts and water, would be, with 

 the fact I have stated, to reduce the genus Paramsecium to vegetal 

 forms — a result which few thorough biologists could sanction. 

 On the other hand their normal ability to dwell in putrescent 

 animal and vegetable fluids, places them on a par with Para- 

 msecium aurelia on its animal side ; and thus their double capacity 

 in this matter appears to give them an intermediate position, 

 touching almost equally the animal and the vegetable series. 



Not less interesting in its general biological bearing is the 

 whole process of fission in this group, especially when its varieties 

 are taken into account. 



