AND ITS EFFECTS UPON ANIMAL LIFE. 



43 



litre jars were used. The arrangements for the absorption of moisture, COj, and for the intro- 

 duction of fresh air, were the exact counterparts of these arrangements in Hammond's apparatus, 

 judging from his description and engraving. Fresh air was supplied at intervals of one-half to one 

 hour. This was accomplished by attaching a graduated asjjiVator to the Geissler potash bulbs 

 containing the Ba(HO)o solution. 



The results obtained in these experi- 

 ments are shown in Table G. Hammond 

 claims that in his experiments a mouse in- 

 variably died within one hour. In our ex- 

 periments all the animals lived over three 

 hours, and some even longer than six hours. 

 The great difference in the duration of life 

 for different animals may be accounted for 

 in the varying susceptibility of different 

 animals of the same species to the atmos- 

 pheric conditions in the jar, but the still 

 greater difference in the duration of life in 

 our experiments, as compared with Ham- 

 mond's results, cannot be attributed to 

 the same cause, and, since it is not known positively what the capacity of the jars was which he 

 used it would be useless to speculate on the point. 



Fig. 5 shows Hammond's apparatus as given in his treatise (Fig. lo, p. 170), and is an accurate 

 representation of the apparatus used by us, except that it does not show the graduated aspirator 

 connected with the free end of the Geissler potash bulbs, by means of which a known amount of 

 fresh air was introduced at stated intervals during the experiment. 



Fir.. 5. — Ilammond's .ipparatus. 



T.\BLE G. 

 THE " H.AMMOND EXPERIMENT.' 



