176 



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



The soil used in the following tabulated Experiments 14-18 had received 

 the following treatment : It was first partially sterilised with toluene, and 

 the antiseptic thoroughly evaporated. This treatment brought the water 

 content of the soil down to 3 or 4 per cent. By adding distilled water, the 

 water content was brought up to 10 per cent., and the soil was left in 

 a corked bottle for two days, in order to allow the water to distribute itself 

 evenly The water content was next brought up to approximately 20 per 

 cent., by the addition of a culture of hay infusion which contained an 

 abundance of active Colpoda cucullus and Pleurotricha grandis. The soil was 

 spread out in a thin layer, and the liquid added as evenly as possible by 

 means of a fine pipette. After this it was put up in a small bottle plugged' 

 with cotton wool, and kept either at 20° C. or at laboratory temperature. 

 The purpose of this treatment was to give every opportunity for the active 

 ciliates added to continue in their free-swimming condition, if that were at 

 all possible. For this reason the culture was not added directly to the dry 

 soil, as it was thought that the bulk of the liquid, on being taken up rapidly 

 by the soil, would do considerable violence to the rather delicate protoplasm 

 of the protozoa, hence the moistening up to 10-per-cent. water content was 

 carried out before the addition of the culture. 



No. 14. 



After 1 hr. 30 m. — No active forms. 



„ 2 „ 40 „ — 1 Col. cucullus, protoplasm fairly clear, a few granules, no food vacuoles. 

 „ 4 „ 5 „ — No active forms. 

 No. 15. 



After 1 hr. 30 m. — No active forms. 



„ 3 „ 45 „ • — 1 Col. cucullus, protoplasm rather granular. 

 ,, 6 „ 15 „ — 1 Col. cucullus, 1 Col. steinii, protoplasm fairly clear. 

 „ 7 „ 20 „ — No active forms. 

 No. 16. — The above soil, air-dried. 

 After 3 hr. 20 m. — 2 Col. cucullus, protoplasm clear, one -with 3 or 4 food vacuoles. 

 „ 4 „ 10 „ — No active forms. 

 „ 5 „ 15 „ — 2 Col. cucullus, not captured. 

 „ 16 „ „ — Many Col. cucullus. 

 No. 17. — 8 - 6 grm. of the above soil, air-dried. 

 After 4 hr. m. — 1 Col. cucullus, protoplasm clear, no food vacuoles, very distinct 

 nucleus without staining. 

 „ 6 „ 15 „ — 3 Col. cucullus, two rather small, protoplasm fairly clear, with a few 

 food vacuoles ; one larger and with quite a large number of food 

 vacuoles. 

 „ 8 „ „ — 2 Col. cucullus. 

 No. 18. — 8"6 grm. of the soil, undried. 

 After 1 hr. 45 m. — No active forms. 

 „ 4 „ 35 „ — 2 Col. cucullus. 



„ 7 „ 15 „ — 1 Pleurotricha grandis, fairly numerous food vacuoles. 



