154 



Mr. W. N. Hartley on the 



[Feb. 8, 



liquid was boiled for ten or fifteen minutes, and heated air was made to pass 

 through the apparatus till the liquid and flask were cool. " When the 

 bulb is quite cool, the necks are sealed by means of a lamp." In Wyman's 

 experiments an apparatus of much the same kind was used ; but the liquids 

 in four cases were boiled for from five to ten minutes in a Papin's digester 

 under a pressure of from two to five atmospheres, or at a temperature of 120° 

 to 150°C. Large flasks of 500 cub. centims., and even 850 cub. centims. capa- 

 city were used, containing 1 7 cub. centims. to 50 cub. centims, or thereabouts, 

 of solution, so that in some cases only -^'of their capacity was occupied ; 

 the air admitted was passed through red-hot iron pipes filled with iron 

 wires. There is a similarity between these two sets of experiments ; the 

 flasks were not entirely in contact with the hot liquid. We see also, from 

 the few words quoted from the description of Child's experiments, that a 

 sufficient space intervened between the red-hot tube and the bulb to allow 

 of the heated air becoming cool before it entered the glass bulb ; it cannot 

 be said, therefore, that the entering air was so hot as to destroy whatever 

 living thing might be attached to the glass. The precautions taken, then, 

 were not sufficient to render the experiments trustworthy, more particularly 

 in the case of Wyman's work, because there he had an immensely large 

 surface untouched by fluid, and naturally he obtained more results in favour 

 of the view of evolution than any other experimenter. Bastian's own ex- 

 periments are open to the same objection * ; in fact it seems that much 

 work has been rendered faulty by this neglect of bringing every part of 

 the interior surface of the containing vessels in contact with the heated 

 liquid. We have positive proof that such is the case when, as Bastian 

 himself states, "it has long been known that a boiled fluid extremely 

 prone to change will not yield infusoria if the vessel in which it is con- 

 tained is filled with the fluid ;" the commercial method of preparing cooked 

 meat depends upon this to a great extent. With respect to the power of 

 vibriones to resist the destructive action of heat, I at one time felt sure, 

 from experiments on hay infusion and decomposing turnip infusion, that 

 they were capable of living after being boiled. This hasty conviction at 

 the moment of observation arose from the fact that the movement of these 

 bodies was the same before and after boiling, and at die same time unlike 

 any example of the Brownian movement with which I was familiar ; but 

 there is no evidence that they were really living in the first case ; it is 

 only a presumption. 



A strong infusion of hay was made with lukewarm water, filtered twice 

 through Swedish paper, and examined under the microscope ; it swarmed 

 with life, especially in the form of bacteria, mostly in rapid motion ; some 

 of these were excessively small, less than 0'00005 inch in length. The 

 liquid was boiled violently for fifteen minutes until two thirds had been 

 evaporated away ; a drop placed under the microscope showed that most of 



* It is worthy of remark that in two out of the four cases in which Wyman heated 

 liquids at a temperature over 100° 0., no organisms were found. 



