PHYSIOLOGICAL VARIATIONS IN PARAMECIUM 501 



These considerations lead us to a further test of maturity as 

 shown b}^ the rapidity of response to the changed condition. 

 This is shown by: 



B. History of the Syracuse dish tests 



A typical conjugation test for the J series is shown in table 6 

 taken from the protocols. The symbols used are as follows: S 



= seeding of rich cultures with progeny from the permanent 

 cultures, S^ S- S' = first, second, and third, and so forth, tests, 

 that is, transference from rich cultures to Syracuse dishes; + 



= symbol for physical condition of the organisms, and means 

 that they are actively dividing. ± = symbol to indicate good 

 physical condition but absence of dividing forms; it marks the 

 beginning of decline in vigor; — = symbol to indicate physical 

 deterioration, loss of size, etc. When this condition is reached 

 conjugation never occurs. X = death of individual Paramecia 

 or all. (36), (2), and so forth = symbols to indicate conjuga- 

 tions and the number of pairs counted. D = discard of the test. 

 K = killed for microscopical examination, i 400 = number of 

 pathological divisions observed. The maximum and minimum 

 temperatures are given for each twenty-four hours. 



In order to test the rapidity of response of conjugating lines 

 to changes from rich cultures to Syracuse dishes we have com- 

 bined all of the protocols up to March 1, similar to that given in 

 the above table. The general results may be seen in the follow- 

 ing table 7 in which the pairs found at different periods of ma- 

 turity are recorded for all the conjugating lines save H' and T' 

 This table may be summarized as follows: After two days in 

 rich cultures none of the lines conjugate. After three days, con- 

 jugations appear on the third and fourth days after transferring. 

 After four days, conjugations appear on the first, second, third, 

 and fourth days after transferring. After five days, conjugations 

 appear on the first, second, and third days but are most abund- 

 ant on the second, while none appear on the fourth. After 

 seven days in rich cultures conjugations appear on the first, sec- 

 ond third, and fourth days, but are most abundant on the sec- 



