Abstract
Lactic acid, when given to a dog, causes the same increase in metabolism that is noticed when a similar amount of alanin is administered. It was also noted that the metabolism was increased after giving 500 c.c. of water in which there was 2.5 c.c. of Liebig's extract of beef, whereas the administration of 150 c.c. of water had no influence whatever. When a large quantity of water was given about 100 c.c. per hour were eliminated in the urine. This indicates that for the transport of a large volume of fluid through the circulation increased energy is needed average, tend to contain one lethal factor after 100 generations—which means about four years in Drosophila. The rate of change for the X in Drosophila is thus about one detectable mutation in four years. This immediately shows us that Drosophila must have a different rate from some other organisms—man for example—for if the X chromosome of man mutated at anything like a similar rate, all the X chromosomes in a female would contain several lethal factors by the time she was ready to reproduce, and none of her sons would be viable.
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