THERMAL DEATH-POINT OF LIVING MATTER. 193 



Timothy Lewis, who has been for some time in Calcutta, carrying on, 

 in concert with Dr. D. Cunningham, important sanitary investigations, 

 has, among other things, directed his attention to the vitality of tape- 

 worm germs in cooked meat. He proved, first, that tape-worm germs 

 are undoubtedly killed by exposure for five minutes to a temperature of 

 135-140 Fahr. ; and then, with a view of ascertaining also how far 

 they would be likely to experience such a temperature in the ordinary 

 process of meat-cooking, he made other important observations having 

 considerable interest for us. Dr. Lewis found that when legs of mut- 

 ton had been put into the boiler almost as soon as the water, their 

 central temperature averaged 140 Fahr. by the time the water around 

 them had reached the boiling-point, and that, after the water had 

 boiled for five minutes, the internal temperature of the legs of mutton 

 which had remained in the boiler had on an average reached 170. 

 This is a practical method of dealing with the question which those 

 skeptical dreamers who talk of the "protective influence of lumps" 

 would do well to imitate. 



After this I may perhaps be deemed fully justified in quoting two 

 very typical experiments for the consideration of those who stave oft* 

 their belief in the occurrence of " spontaneous generation" either by 

 relying upon insufficient reasons for doubting the influence of boiling 

 water, or because of their following Pasteur, Cohn, and others, in suppos- 

 ing that certain peculiar Bacteria-germs are not killed except by a brief 

 exposure to a heat of 227 or 230 Fahr. For, even if we could grant 

 them these limits, of what avail would the concession be toward stav- 

 ing off the dreaded admission of the occurrence of " spontaneous gene- 

 ration," in the face of such experiments as those which follow? 



Experiment I. A strong infusion of turnip was rendered faintly 

 alkaline by liquor potassse, and to this a few separate muscular fibi-es 

 of a codfish were added. Some of this mixture was introduced into 

 a flask of nearly two ounces' capacity. Its neck was drawn out and 

 afterward hermetically sealed by the blow-pipe flame, while the fluid 

 within was boiling. When thus closed the flask was about half full 

 of fluid. It was then introduced into a digester which was gradually 

 heated, and afterward kept at a temperature of 270-275 Fahr., for 

 twenty minutes, though it seems also well to point out that, if we include 

 the time taken for the w r ater of the digester (in which the closed flask 

 was immersed) to attain this heat, and also again to cool down to 

 230 Fahr., this flask was exposed to temperatures above 230 Fahr. for 

 one hour, as I myself carefully noted at the time. When withdrawn 

 from the digester the closed flask was kept at a temperature of 70-80 

 Fahr. for eight weeks, and during part of this time it was exposed to 

 the influence of direct sunlight. After it had been ascertained that 

 the flask was free from all crack or fault, its neck was broken, in order 

 that its contents might be examined. The reaction of the fluid was 

 found to have become decidedly acid, and it had a sour though not 



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