350 SUMMARY OF CURRENT RESEARCHES RELATING TO 



would be if another glacial period suddenly arrived. The only reward, on 

 the other hand, for successful and almost inconceivable perseverance would 

 be the discovery of truth, and the reinforcement of Darwin's sublime 

 generalisation. But, for the sake of these, which always satisfy the noble 

 ardour of science, Dr. Dallinger has given as many years of his life as were 

 spent by the Greeks in the siege of Troy, and has apparently won a scien- 

 tific victory, the value of which is as signal as his ingenuity and devotion 

 are admirable. 



We will endeavour very briefly to describe the method and the outcome 

 of his most remarkable experiments. The group of microscopic monads 

 were put under the lens in a well-fitted water-cell at their usual temperature 

 of 60° F., the apartment, the apparatus, and all round being carefully kept in 

 precise unison. The Doctor then spent the first four months of his observation 

 in raising the temperature time after time by stages less than one-sixth of 

 a degree, until his swarm of protozoa had reached the new and advanced 

 reading of 70'^ F. This change, nevertheless, had no more disturbed them 

 than that experienced by a British family when it migrates from London 

 to Cape Town ; the life-history of each grouj) remained unaltered ; they 

 moved, gyrated, fed, and split themselves into new individuals in just the 

 same manner and within much the same period as before. When, however, 

 three more degrees had been added to the seventy, the monads showed signs 

 of being decidedly inconvenienced. They were neither as lively nor as 

 productive as formerly ; yet, by keeping them exactly at this range during 

 two quiet months they regained their full vigour, and might be compared 

 to emigrants who had become seasoned by surviving the first hot spell in a 

 tropical country. They could now stand — by gradual steps of increase — 

 the enhanced heat of 78°, which was reached at the commencement of the 

 twelfth month. Yet here, again, a long pause was found to be necessary ; 

 the new generations of those silver specks of life under the glass were not 

 all alike strong enough to live and thrive. What answers to sunstrokes and 

 fevers with us had caused vacant spaces to appear in the water-drop, and it 

 was only when the monads showed themselves once more lively and prolific 

 by a long era of repose that the careful Doctor administered a further dose 

 of caloric. During eight years and a half did he thus slowly and un- 

 weariedly proceed in the same course, augmenting the heat of their sur- 

 rounding element now and then by slow and slight additions, pausing 

 afterwards for months to give the minute creatures time to accommodate 

 themselves when signs were visible that they were under difficulties, and 

 always going forward to new trials of endurance when they had recovered. 

 In this manner, after all those many years, Dr. Dallinger brought his small 

 patients to the astonishing range of 158° F., at which the latest generation 

 appeared ' as jolly as sand-boys.' It is not possible to say how much 

 farther their tiny constitution could have been trained to defy increasing 

 warmth, because the research was at this point accidentally terminated ; but 

 it will be seen that the Doctor had brought the little people of his drop- 

 world to sustain a heat nearly one hundred degrees higher than the flourish- 

 ing point of their ancestors, any species of which, if taken at the beginning, 

 would have been completely and instantaneously killed in water of one 

 hundred and forty degrees. When we have added that these minute 

 salamanders perished directly they were put back into their ancestral 

 medium of sixty-five degrees, if will be manifest that the indefatigable 

 Doctor had, by the magic of science, efiected a miracle of Nature almost as 

 striking as if the Protococcus nivalis, which stains the Arctic snow with 

 crimson, had been transformed into the great grasses and feathery bamboos 

 which clothe the burning sides of a mountain under the Equator. 



