EFFECTS OF HIGH TEMPERATURES 49 



yellow solution, containing twelve drops of the 

 dilute sodium silicate and six drops of the iron 

 solution to the ounce of distilled water; and these 

 particular solutions were not at all decomposed- 

 that is, there was only a small amount of yellow- 

 ish deposit in each, while the fluid itself remained 

 of a pale yellow colour. Moreover, in five out of 

 these six tubes organisms were found, when they 

 were opened after nine to eleven months 1 (see 

 Plate 5, Figs. 25 and 28). 



At other times, when the yellow solution has 

 been decomposed so as to leave only a clear, colour- 

 less fluid above the deposit, this latter, instead of 

 being composed of mere minute, glass-like frag- 

 ments, has been in the form of a copious reddish, 

 gelatinous material, in which organisms have some- 

 times been found and sometimes not. 



Again, there are distinct colour variations, re- 

 sulting from the use of different proportions of 

 sodium silicate when the quantity of the iron pre- 

 paration remains the same in each case that is, 

 eight drops to the ounce. Thus, with two drops 



1 Six tubes, charged with the colourless solution, containing 

 twelve drops of the dilute sodium silicate to the ounce (Nos. 34, 

 35, 36, and 40, 41, 42), were also heated to 135 C. for five 

 minutes ; and in three of these tubes organisms were found, when 

 opened after eight and a half or eleven months (see Plate 4, 

 Fig. 24; and Plate 5, Figs. 26, 27). 



4 



