102 Transactions of the 



placing within 80^ C. Nevertheless, if there are any solid particles, 

 such as cheese, or turnip, or viscid earth, or if the boiling is not so 

 conducted as to secure an equal temperature throughout every part 

 of the flask, some adults even may escape. With proper precautions, 

 it has been shown by Cohn, Horwath, B. Sanderson, and even by 

 Bastian and Huizinga themselves, that this may happen. 



But as to germs or sporules, we have now shown as a matter of 

 fact that they do resist a heat which destroyed not only adults, but 

 immature forms of those species that are born with the vitahty of 

 the sarcode in complete action. How can this be explained ? Is it 

 reasonable to suppose that in bodies so inconceivably minute there 

 can be special arrangements for heat resistance which are not found 

 in the adults ? There is no argument that we are acquainted with 

 that makes this supposition impossible. Their size, it is true, must 

 be less than the -g-^oVTroth of an inch, even where visible, for they 

 are only barely so to the gV^h. But what is this, after all, to the 

 minuteness of the molecules of matter ? According to Prof. Tait, " In 

 a single drop of water there are a thousand quadrillions of ultimate 

 particles. Each particle in a drop of water is to the entire drop as 

 the size of a walnut is to the earth." Now the molecules of living 

 matter are undoubtedly extremely more complex and larger than 

 those of water. Yet it has been shown by the experiments of 

 Davaine,* and confirmed by Clementi and Thin,t that the living par- 

 ticles which produce septicaema can carry on an infinite multiplication 

 of their numbers and cause the death of the animal into whose blood 

 they are inserted, and that in a quantity only corresponding to the 

 10 trilKonth of a drop. Between this and our sporules the o-TJiTTjiTTr^ili 

 of an inch there is surely " ample room and verge enough " for a 

 comphcated protective structure, which should have the power to 

 resist the difi'usion of heat, at least for a time. For the germ may 

 be emitted with its sarcode in a fixed state, not having any inter- 

 change of fluid with the surrounding medium, and thus differing 

 wholly from the adult or immature viviparous forms. 



"What may be the nature of this protecting envelope or medium 

 it is at present impossible positively to say ; but it will be remem- 

 bered that in every case in which we have seen a monad-sac emit 

 sporules, it has always been in what we can only describe as a 

 " glairy fluid " ; and when we remember the remarkable effects of 

 the spheroidal state of water, we must be more than cautious in 

 denying that such protecting envelopes may be formed in such a 

 medium by analogous means. Indeed, we have the guide of facts 

 in this matter, as the results of experiments on the desiccation of 

 rotifers will serve to show.t 



* 'Comptes Rendus,' 1872. 



t 'Edinburgh Medical Journal,' July, 1873. 



X 'M. M. Jouni.,' vol. ix., 201. 



