32 DR. E. KLEIN. 



the bacillus forming fluiFy masses of convoluted filaments; 

 where these appear the gelatine becomes liquid ; and as the 

 growth gradually extends downwards, deeper and deeper layers 

 of the gelatine material become liquefied, the bacillus growth 

 of course occupying the deepest layer of the liquefied material ; 

 the liquefied layers above remaining perfectly limpid. In this 

 way the growth gradually comes to lie deeper and deeper, and 

 when the deepest layer of the gelatine has become liquefied, 

 the bacillus mass is at the bottom of the test-tube. When this 

 stage is reached the growth does not differ in any respect from 

 one in a test-tube of pure pork broth. The same changes, de- 

 scribed above, of diminution and gradual dwindling away of 

 the bacillus mass is also here noticed. 



Differing, however, from the bacillus growth in pure pork 

 broth, the bacillus growth on the surface of the gelatine pork 

 is capable of spore formation, as long as the growth is still 

 close to the surface ; but as the superficial layer of the gelatine 

 becomes liquefied by the bacillus growth, this latter gradually 

 takes a deeper position, and since the spores previously formed 

 again germinate into bacilli, a time arrives when no more 

 spores are formed in the bacilli. When a sufficient amount of 

 the gelatine pork has become liquefied so that the bacillus 

 mass being placed at the lowest part of this liquefied portion 

 is away from the surface, no more spore formation is observed ; 

 the bacillus threads, however, continue to increase in length 

 and numbers till all the nourishing material is exhausted. But 

 I have some instances where no spore formation took place 

 even at the commencement ; that is the case when the inocula- 

 tion of the gelatine pork in test-tubes takes place (though it 

 be at the surface) at a point between the gelatine and the glass. 

 Here the growth increasing burrows itself at once into the 

 depth and liquefies the gelatine on one side in the shape of a 

 pit or channel passing downwards, and as the bacillus mass 

 occupies the deepest position in this pit of liquefied gelatine it 

 becomes removed from the surface, Avhile yet only composed of 

 bacillus threads. And the growth proceeding into the depth 

 and from here into the sides it may happen that the whole 



