The President's Address. By the Rev. W. H. Ballmger. 197 



For the first two months nothing that I could really be sure of 

 was visible to indicate such change ; but M. BalUngeri has the pecu- 

 liarity of being almost entirely, in the normal state, free from vacuoles in 

 the sarcode. I had noted and drawn the other forms several times much 

 more vacuolated than was usual ; but I now, at between two and three 

 months after 78'' had been reached, observed frequently that T. rostratus 

 and D. Drysdali were also vacuolated ; and in the course of a month 

 this was not only abundant, but far more the rule than the exception. 



In figs. 1, 2, 3, plate YI., are presented fair average drawings of the 

 three forms in their normal condition, and in figs. 4, 5, 6, 7, and 

 8, 9, 10, 11, and 12, 13, 14, 15 are shown the successive states pre- 

 sented by average specimens, taken in the case of each monad during the 

 fourth and fifth months after being static at 78'' Fahr. 



This vacuolation was not necessarily permanent. The vacuoles could 

 often be seen to gradually get nearer to each other and unite into a 

 larger one ; and in the process of fission the vacuoles would often divide, 

 and in some cases partly, or even wholly, disappear. But in a sexual 

 fusion of two forms all this vacuolation disappeared, and the sac presented 

 a perfectly normal condition. 



After the fifth month I found, on careful trial, that I could without 

 much discoverable inconvenience to the organisms raise the temperature 

 a degree, and in the course of three months, by very dehcate increments, 

 I had reached 80'. 



During this time the vacuolation, which was, as I have said, no 

 proper feature of these forms as I knew them at normal temperatures, 

 disappeared very gradually, and they were, in condition, form, and activity, 

 much as they were at 60^. 



The advance from this point had to be gradual ; either too large an 

 increment, or too short an interval of time, again wrought visible damage, 

 and had to be at once corrected ; but as the temperature advanced, there 

 was no alteration anywhere perceptible in the sarcode of the organisms ; 

 nor did they alter in the least as to the details of fission or sexual fusion. 

 The time occupied and the manner were as described for ordinary 

 temperatures. 



By very slow elevation of temperature, extending over nearly nine 

 months, I reached 93^ and during all this time I could detect no 

 divergence from the same organisms when seen at 60 'Fahr. They resented 

 a too rapid elevation of temperature, and I had constantly to return to 

 the last static point for longer or shorter periods before a sure advance 

 was made. It was evident that a physiological adjustment had to be 

 brought about, adapting the organisms to each fresh elevation of the 

 thermostat, before any successful progression could be made. 



But beyond the point of 93"" I could not go without causing aU three 

 of the monads to surrender to torpor and death, until I had submitted to 

 what proved to be a prolonged continuance of the static 93^. 



I tried to elevate the heat by most dehcate advances, the smallest 

 fraction of a degree of which the apparatus was susceptible, at intervals 

 of one month for three months successively, but with such adverse results, 

 visible in a couple of hours, as made it necessary to go back to a lower 

 point than 93^ in order to restore complete vigour. 



