EFFECTS OF STRYCHNINE UPON RATE OF LEARNING 165 



given by subcutaneous injection; on the following two days only 

 water was given; and again the drug on the next two days. To 

 control the effects of practice during the test three rats in each 

 group received the drug on the first two test days while the re- 

 maining three received water on these days and the alternations 

 were continued regularly with each three. The three groups 

 were given alternately (1) water, 0.10 cc. and strychnine sul- 

 phate, 0.10 mgm.; (2) water, 0.10 cc. and strychnine sulphate, 

 0.05 mgm.; (3) water, 0.10 cc., and caffeine, 0.50 mgm. 



The data obtained in the experiment are summarized in 

 table 11. In the table the averages of the first ten trials are 

 based upon sixty trials, or ten for each rat. The remaining 

 averages are based upon thirty trials for each rat or one hundred 

 and eighty trials altogether. The significant figures for de- 

 termining relative efficiency with and without the drugs are the 

 rate of running and the number of errors. The differences in 

 rate are not great: for group 1, the rate of running, under the 

 influence of the drug is 114 per cent; for group 2, 108 per cent; 

 and for group 3, 91 per cent of the water control. These dif- 

 ferences are in inverse proportion to the number of errors made 

 and are probably due to the time lost in stopping and turning 

 when errors were made. 



The superiority of the animals under strychnine as measured 

 either by the excess distance traversed or by the counted num- 

 ber of errors is quite marked. Under strychnine group 1 made 

 59 per cent fewer errors and traversed 64 per cent less dis- 

 tance than when without strychnine. Under the same conditons 

 group 2 made 11 per cent fewer errors and covered 28 per cent 

 less distance. 



Under caffeine the rats of group 3 made 26 per cent more 

 errors and traversed a distance 29 per cent greater than without 

 the drug. 



All the rats, with one exception, in groups 1 and 3, in which 

 the greatest effects of the drugs are evident, were affected in 

 the same way by the drugs. The individual averages of the 

 animals in these groups are given in table 12. In group 1 

 every one of the animals made fewer errors while under the 



