'fE. 





othe 



rs hav 



I hav 



ef: 



esi 



requf. 



I 



^'^^"y sealed, 



I 



1 



^fter it had fe; ' 

 ' fluid had b- ' 



■apid evapoi 

 3n of turnip! k 



ve or SIX 



I 



\ 



^L 



mounted in lu, 



earance often:;: 



le tissue, enctedi; 



sion he nicU 1= 



At the exp* 



the solution, at ■-■ 



ij; 



1 



,t after a time ^ 



I 



iciomaldell^''" 



-iouslj ««■ 



:;::> 



> 



pnt. 



Or a 



drop 



) 



. aniii^^ 



;..icuie^«;: 





Irop- ;ion- 



■ of th^ r .n/ 



le 



times 





natur 



aH'^^ 



TI/£ BEGINNINGS OF LIFE. 



'^9^ 



manner above mentioned^ it is not difficult — with the 

 stage of the microscope in a horizontal position — 

 to bring into the field of view a portion of the film, 

 which either contains no visible^ particles, or only 



a small number, such as can be easily counted. With 

 the slip resting on one of Stricker^'s hot-water plates 

 maintained at a temperature of ^^-^^ F., it may be 

 found that, in the course of three or four hours, faint 

 and ill-defined whitish specks, less than 



5 0" 



m 



diameter, make their appearance pretty evenly dispersed 

 throu^^hout the field of view. These are at first almost 

 motionless — exhibiting only the merest vibrations, but 

 no progressive movements. They gradually become 

 more distinct, assume a sharper outline, and after 

 a variable time some of them develop into distinct 

 Bacteria'^. At first they exhibit gentle oscillations and 

 tremblings only, though gradually they display the more 



The study of the 

 mode of origin of these primordial living forms is, in- 



characteristic darting movements. 



more 



e 



fact that they remain comparatively motionless for a 

 long time after their first appearance, and also continue 

 faint and much less refractive than when in the more 

 mature condition. Hence it becomes a matter of the 



' Working with a magnifying power of looo diameters. 



^ The shortest time in which I have seen Bacteria develop in such 

 a film has been one hour and a half. More frequently, however, three 

 hours have elapsed, and sometimes longer still, before distinct Bacteria 

 have made their appearance in the field of view. 



