Maech 20, 1908] 



SCIENCE 



443 



1. Minute doses of alcohol (1/2,500) 

 will decrease the rate of division at one 

 period of the life-cycle, and increase it at 

 another period of the life-cycle. 



2. When alcohol (1/2,500) increases the 

 division-rate, the effect is not continuous, 

 but gradually diminishes, and finally the 

 rate of division falls below that of the con- 

 trol series and remains there. 



3. An increase (doubling) of the amount 

 of alcohol administered, however, will again 

 cause a more rapid cell division for a lim- 

 ited period, but again this effect is not con- 

 stant and the rate of division falls below 

 the control. Up to the present time (De- 

 cember 26, 1907) the alcohol has been in- 

 creased in amount (doubled) three times, 

 always with the same result. 



4. Treatment with alcohol lowers the 

 . resistance of the organisms to copper 



sulphate. 



The Acclimatization of Stentor to Alcohol: 

 J. Frank Daniel, Johns Hopkins Uni- 

 versity. 



Solutions of alcohol above 4 per cent. 

 were found to be early destructive of the 

 protoplasm of Stentor coeruleus. In a 

 strength of 1 per cent, or lower, however, 

 the animal lived without apparent injury. 

 At the end of four days stentors kept in 

 a weak solution had so adjusted themselves 

 as to be able to live in a slightly stronger 

 percentage; further, when killed in a 

 strength of 6 per cent, they gave an av- 

 erage resistance period of twice the control 

 value. 



By rearing these ciliates in a weak solu- 

 tion of alcohol plus water of very great 

 purity the factor of food may be elimi- 

 nated. In such a medium they gained 

 markedly in resistance, thus demonstrating 

 that the lengthened period of resistance 

 was due to the direct effect of the alcohol 

 upon the protoplasm and not to an indirect 

 effect upon the food conditions of the cul- 

 ture. 



In solutions weaker than 0.4 per cent, 

 no acclimatization was indicated until after 

 the second day. Those kept in a constant 

 strength of either 0.5 per cent, or 1 per 

 cent., however, showed a clear adjustment 

 at the end of the first day, as, for example, 

 reared in 0.5 per cent, and tested in 6 

 per cent., average resistance 127 seconds, 

 control value 99 seconds ; in 1 per cent., 166 

 seconds, with a control of 120 seconds. In 

 all cases there was a noticeable increase on 

 either the fourth or the fifth day which 

 marked the maximum of resistance for the 

 series. Following this maximum there was 

 a gradual decline, the cause for which is, 

 as yet, undetermined. 



Inheritance in Protozoa: H. S. Jennings, 

 Johns Hopkins University. 



Some Maturation Stages of the Mouse Egg : 



J. A. Long. 



E. L. Mark presented some of the con- 

 clusions reached by Mr. J. A. Long— a stu- 

 dent in Harvard University— especially as 

 to the number of chromosomes. It was 

 imagined a year ago that possibly the num- 

 ber found by Sobotta and confirmed by 

 Kirkham (twenty- four somatic, or twelve 

 reduced) differed from the number counted 

 by Tafani and the author (twenty, 

 reduced) because different breeds or 

 strains of mice actually presented different 

 conditions in this respect. But the cour- 

 tesy of Professor Coe in loaning some of 

 Dr. Kirkham 's preparations for study has 

 led to the belief that differences in the 

 number of chromosomes counted is due 

 rather to the complications of form and 

 grouping presented by the chromosomes 

 than to any difference in the actual num- 

 ber of them. 



A critical study of a large number of 

 preparations— between five hundred and a 

 thousand— has shown that, while the 

 chromosomes present a variety of forms at 

 different stages, they are really— as might 



