174 Mr. T. Goodey. A Contribution to our [May 19, 



occur in any abundance until two or three days after inoculation. It was 

 necessary, therefore, to determine, if possible, the period of time elapsing 

 between inoculation and the appearance of the first active protozoa in the 

 culture. 



Preliminary experiments revealed the fact that active ciliated protozoa 

 could be obtained in a soil culture in the short time of four and a half hours, 

 and by using the galvanotactic method just described it has been possible to 

 obtain a considerable amount of information. 



In the following experiments, different soils have been used and com- 

 paratively large quantities have been taken in order to increase the chance 

 of finding any possible free-living protozoa in the soil. The larger the 

 quantity of soil, within limits, the more probable is it that active protozoa, 

 if present, will come out into the culture liquid. 



No. 1. — Manured soil from Barnfield, very moist. 

 After 1 hr. 40 m. — 1 Colpoda cucullus, only seen once, protoplasm rather granular at 

 posterior end. 



1 Vorticella microstoma, free swimming, cylindrical, aboral ciliary ring, 

 no food vacuoles, protoplasm clear. 

 „ 4 „ „ — 1 Enchelys sp. ?, protoplasm clear. 



This soil had been stored for six weeks under conditions favourable to bacterial activity, 

 and presumably to protozoal activity also. 



No. 2. — Same soil as in 1. 

 After 4 hr. 25 m. — 1 Col. cucullus, protoplasm rather granular, not stained with neutral 

 red, no food vacuoles. 

 Many Col. steinii, protoplasm clear. 



3 or 4 Gonostomum affine, protoplasm very clear, nuclear areas easily 

 visible. 



No. 3. — Manured soil from Barnfield. 

 After hr. 40 m.— No active forms. 



„ 1 „ 30 „ ■ — 1 Col. cucullus, protoplasm rather granular, no food vacuoles. 



1 Col. steinii, rather granular, nucleus very clear on staining. 

 1 Balantiophorus elongatus, protoplasm clear. 

 „ 3 „ „ — 1 Col. cucullus, 2 or 3 Col. steinii, 1 Gonostomum affine, 2 Balantio- 

 phorus elongatus, 2 Spatkidium spathula. 

 This soil had been air-dried, subsequently moistened and stored at laboratory- 

 temperature since October, 1910, in a bottle plugged with cotton wool. 



No. 4. — Manured soil, Hoosfield, fresh and moist. 

 After 1 hr. 20 m.— No active forms. 

 „ 2 „ „ — „ „ 



„ 3 „ 45 „ — 1 Col. steinii, very active, protoplasm clear. 



1 Bal. elongatus, protoplasm clear. 

 No. 5. — Manured soil as in ]. 

 After hr. 30 m. — No active forms. 

 „ 1 „ 15 „ — 

 „ 2 „ 15 „ — „ „ 



