88 The Conditions of Infusorial Life. 



to the air for thirty-five days without giving any signs of infu- 

 sorial life. 



Another curious set of experiments was made with frag- 

 ments of human bone ; all the vessels being placed under 

 similar conditions. These vessels were filled with the same 

 filtered water. In the first were five grammes of the skull of an 

 Egyptian, which M. Pouchet brought from the necropolis of 

 Sakkara ; the second contained the same quantity of a Merovin- 

 gian skull, and the third was supplied with pieces from a con- 

 temporary cranium. Each was placed under a bell-glass, and 

 left alone for a month, at the expiration of which time the 

 Egyptian bone liquor exhibited a numerous family of epistylis, 

 enchelis, and vibrions. The Merovingian liquor was rich in 

 Glaucoma scintillans, to the extent of legions, together with a few 

 vorticellids ; neither of which appeared in the first glass. The 

 broth made from a contemporary skull had its own peculiar in- 

 habitants in the shape of kolpods. The three vessels were then 

 placed under one bell-glass, but they still maintained the pecu- 

 liarities of their population. 



M. Poxichet remarks, that it is not only the nature of the 

 fermentable substance, but its quantity, that determines the 

 kind of infusoria that appear. For example, he took similar 

 vessels, placing in each thirty grammes of spring water, but dif- 

 ferent quantities of hay. They were all covered by bell-glasses, 

 kept at about 75° Fahr., and examined in a week. The first, with 

 ten grammes of hay, had a thick pellicle, and the liquid con- 

 tained a great quantity of Kerona lepus, some pear-shaped ani- 

 malcules, and large cysts. The pellicle likewise contained a 

 quantity of small cysts. The second vessel, with five grammes 

 of hay, had a thinner pellicle, no keronians, a few piriform 

 creatures, and fewer cysts. The third vessel, with two grammes 

 and five decigrammes of hay (that is, about thirty -three grains), 

 showed no keronians, no large cysts, a few small cysts, and 

 very minute indeterminable animalcules. The fourth glass, 

 which had one gramme twenty-five centigrammes of hay (about 

 nineteen grains), presented infusoria, " infinitely less than those 

 in the first vessels, and of indeterminable character." 



Pouchet considered, somewhat hastily, that these experiments 

 proved that the air was not the vehicle of the germs, and that the 

 quantity of the decomposing matter exercised some peculiar in- 

 fluence. To the latter part of this supposition, he calls it a 

 " puerile objection" to affirm that the requisite aliment existed in 

 different quantities. It should however be remembered, that a 

 proximate analysis of hay would show that it contains certain sub- 

 stances in exceedingly small proportions, so that the fermentation 

 of a little bit would only give rise to an infinitesimal quantity of 

 particular products. It has long been known that a large mass of 



