58? 



were rcali/.ed, 10 that the germ theory fulfills the test of 



ry, that test Ming ti 



When "naked or almost na^ ^ of prot"p!a-m " 



are spoken of. the imagination H drawn up>n, not the 

 objective truth of Nature. Such words sound like the 

 knowledge where knowledge is really nil. The 

 possibility of a " thin coveriug " is conceded by those who 

 speak in this way. Such a covering may, however, exer- 

 cise a powerful protective influence. A thin pellicle of 

 india-rubber, for example, surrounding a pea keeps it 



in boiling water for a time sufficient to reduce an un- 

 covered pea to pulp. The pellicle prevents imbibition, 



on. and the consequent disintegration. A greasy or 

 oily surface, or even the layer of air w hich clings to certain 

 bodies, would act to some extent in a similar way. " Tin- 

 singular resistance of green vegetable.- 

 says Dr. William Roberts, "appears to be due to some 

 peculiarity of the surface, perhaps their smooth glistening 

 epidermis which prevented complete wetting of their sur- 

 faces." I pointed out in lb?C that the process by which an 



-pheric germ is wetted would be an interesting sub- 



: investigation. A dry microscope covering-glass may 



i to float on water for a year. A sewing-needle 



may be similarly kept floating, though its specific gravity 



is nearly eight times that of Were it not for some 



.-pccilir relation between the matter of the germ and that 



of the liquid into which it falls, wetting would be simply 



rodent to all development there must be 



an interchange of matter between the germ and its en\ 



; and this interchange must obviously depend upon 

 the relation of the germ to its encompassing liquid. Any- 

 thing that hinders this interchange retards the destruction 

 of the germ in boiling water. In mv paper published in 

 tl.e -Philosophical Transactions" for 1877, I add the 

 following remark: 



It !.< . It to w* that the surface of a seed or eenn 01*7 be 



K affrt'i l>y dmtirratinn an-l <>tl,rr cau*e an practically to prevent 

 btlwM it an body >f a 



.uy be so ioduratetl l.\ tin.> un<i ilrvneM an to ni*t 

 ;iil!\ thu : lN-tween it ' M.!- 



: DC .liU'n-ult !.. ran-.- si,, -1, ii jr,. rm (,, i,,,|. 



.re necemary to produce the awelling and imftening 



,.r.--. -.1.- Hi) .l.-Mnu-iion in 11 li.|uul ..1 lu K l, !,!,.].. r.itur.- 



