DEPARTMENT OF GENETICS. 109 



tested daily for one to four months. The detailed account of methods may 

 be deferred to the final report. Dr. MacDowell reports as follows : 



"The most important result so far obtained from the dose of 3 c.c. for 

 45 minutes is that the criteria used bring out characteristically different be- 

 havior in different mice. Some mice, week after week, give the same reac- 

 tions; many will regularly turn over at once on coming out of the anesthetiz- 

 ing bottle, run along, and hold back from the edge of the table; others, 

 quite as regularly, will turn over and run along, but fall off the edge three 

 times in succession; again, a mouse will always sit still for a while after 

 turning over at once, and others will lie on their sides for an hour or two 

 before turning over at all. Besides these cases of uniform behavior, all 

 degrees of variable behavior are found, but in the latter cases as well indi- 

 vidual characteristics are evident; a mouse will usually turn right over, but 

 every four or five days it will lie on its side for a while; another will never lie 

 on its side, but will usually fall off the edge, with once in a while a day of 

 holding back from the edge. A curious type of incidental behavior is shown 

 by members of one litter, which, after partial recovery, frequently raise their 

 heads, pointing their noses straight up in the air, and then slowly wave 

 one front paw up and down. Nothing approaching this behavior has been 

 seen outside this litter. 



"When the mice are left in their bottles every day until they are drunk, 

 the criteria of comparison become reduced to the time necessary to produce 

 motionlessness and the time for recovery. Records have been taken from 

 22 mice so treated. By this treatment the individual differences are less 

 strikingly brought out, although certain ones clearly take more time to 

 become drunk and others as clearly take more time to regain control. 



"The existence of individual differences opens the way for the discovery 

 of strain differences. Although the experiments thus far carried out have 

 been primarily devoted to the study of methods, one case may be cited which 

 suggests that a genetic difference may be involved. From two different Hues 

 two litters, of 5 and 6 mice, respectively, all of the same age, were started on 

 the same day with the 45-minute alcohol treatment, and thereafter they were 

 dosed simultaneously. All the males lived in one box and the females in 

 another. Both males and females of one Htter regularly turned over, ran 

 along, and held back from the edge of the table, while all of the other litter 

 either lay on their sides, sat still, or fell off the edge. 



" Of interest is the rapid accommodation made by the majority of mice to the 

 hght dose. They generally lay on their sides after the first treatment at a 

 month old; the time varied from 30 minutes to 2 hours. After 5 or 6 days 

 the mice would usually turn over at once and go away. There is little evi- 

 dence of further accommodation after the first week, even though the treat- 

 ment be continued for 4 months. These specially susceptible ones that con- 

 tinue to lie on their sides throughout the treatments do not show a gradual 

 shortening of the time spent on their sides. In the case of the heavy treat- 

 ment there is an initial period of lengthening treatments, which soon ends, 

 and in some cases the period of treatment then remains fairly constant, 

 while in others it declines. Where there is a decline it is evident that the 

 mouse is losing rather than gaining resistance. 



"The effects of temperature on alcoholization and recovery are being 

 studied; but so far are not found to be marked." 



New Mouse Mutations. 

 Both at Cold Spring Harbor and at Orono, Maine, eye abnormalities have 

 been discovered in non x-rayed lines. The Orono mutant, discovered by 



