253 
Ellis.— The Life-history of Bacillus hirtus . 
the material before inoculation was invariably boiled for two minutes at 
ioo° C, every individual was the product of the germination of a spore. The 
motion exhibited at this stage is of the nature of an undulating and pulling 
movement. When observed in 2-5-celled individuals (Fig. 11) it is very 
distinct, more so in fact than in single-celled individuals, probably because 
they are slightly older, as evidenced by the fact that in them division has 
occurred once or twice since germination. In longer threads the inertia 
is too great to produce actual movement, but it is evident that there are 
cilia even at this stage by the manifest strains that are exerted, which is 
different from the slight trembling due to molecular movement. I was not 
successful, however, in obtaining cilia preparations from cultures of this age. 
In a fifteen hours old culture the motility is very pronounced, the 
individuals being as active as any bacillus at its most active stage of 
motility. Fig. 45 is a micro-photograph and shows two individuals covered 
with cilia. As seen the cilia are undoubtedly peritrich, so that it is 
necessary to allocate this species to the genus Bacillus. The stain which I em- 
ployed for cilia preparations was Night-blue, which is made up as follows : — 
^ | 1 gram Tannin to 20 c.c. Water. 
‘ ( 1 gram Alum to 20 c.c. Water. 
B. J gram Night-blue to 20 c.c. Absolute Alcohol. 
Add A to B, not B to A. 
The method of preparation of cilia is as follows - 
A coverslip is washed very clean with alcohol, being finally passed 
through the flame. A glass slide is washed in the same way. A drop of 
water is placed on three places on the glass slide. Into one of them the 
material is inoculated. After passing the inoculating platinum loop through 
the flame and cooling it, a portion from the inoculated drop is placed into 
the second drop. In the same way a portion from the second drop is 
placed into the third drop. In this way the third drop though it contains 
fewer bacteria is almost clean, with scarcely any stainable matter except 
bacteria in it, so that clean preparations can be obtained. A portion from 
the third drop is now smeared over the clean coverslip. Care must be 
taken that the coverslip is so clean, that when the smearing takes place, the 
liquid does not roll itself up, but tends to spread out over the surface of the 
coverslip. The smear is usually performed with a platinum wire. To 
facilitate the process of smearing about 3 m.m. of the end of the wire is 
bent at right angles to the rest of the wire, the smearing being performed 
by this bent end. After the smear dries up, the stain is passed through a 
filter, allowed to drop on the coverslip and allowed to act for two minutes. 
The coverslip is then washed, dried, mounted in Xylol and examined. 
This method of procedure is simpler and more expeditious than 
Loffler’s method, and in cases where the individuals are actively motile is 
always to be recommended. This is a good stage for examining the kinds 
