376 SERGIUS MORGULIS 



the brain is essentially dynamic, its elements constantly throb 

 with activity, and now one, now another dominates over the 

 higher functions. 



In concluding this section of the paper I cannot forego to quote 

 the following picturesque sentence of Pawlow: ' If it were 

 possible to look through the skull and if the region in the hemi- 

 sphere of optimum affectibility were lighted up, we might see in 

 the thinking conscious human being a bright spot of fantastically 

 ragged outline, of perpetually changing form and size and migra- 

 ting over the hemispheres surrounded by more or less complete 

 darkness hanging over the rest of the hemispheres." 



Frideman, S. S. — Further Contributions to the Physiology of Differentiation of 

 External Stimuli. 



The object of this investigation was to find out where the differentiation of an 

 auditory conditioned stimulus takes place: in the auditory analyser or in that 

 cortical portion of the nutritive center upon which the corresponding unconditioned 

 stimulus acted. The procedure was this: a conditioned reflex to a sound of 2,600 

 vibrations per second was worked out on the basis of direct salivary stimulation 

 with meat-powder, and the stimulus was differentiated for a tone of 2,324 vibrations. 

 Then a conditioned reflex to the higher tone was worked out with the aid of 

 acid irritation and the differentiated tone tested again. If the differentiation still 

 exists — as it was actually found to be the case — it means that the specialization 

 occurs in the auditory centre. The author further found that it is easy to establish 

 a conditioned reflex on the basis of the meat powder after such has been established 

 to acid, but not vice versa. 



Tchecotareva, O. M. — Further Contributions to the Physiology of Conditioned 

 Inhibition. 



The conditioned inhibition is proven to be a fof m of internal inhibition. The effect 

 of this inhibition is subject to summation by repetition. By persistently testing 

 the reflex after the inhibition the reflex may be released of its influence. Irrelevant 

 stimuli, especially of the same analyser, destroy the inhibitory action. The process 

 of conditioned inhibition remains potent even after some conditioned reflexes have 

 been freed of its influence. 



Theocritova, U. P. — Time as a Conditioned Stimulus of the Salivary Gland. 



By stimulating the gland with food at strictly regular intervals a specific salivary 

 reaction may be formed on a time basis. The conditioned reflex thus established 

 resembles exactly other conditioned reflexes. It is not very stable, however, and 

 wanes after the first failure of reinforcement by the unconditioned stimulus. The 

 nervous system is capable of very minute differentiation of time, and the 29th 

 minute is clearly distinguished from the 30th in a thirty-minute period. The specific 

 stimulus of the salivary centre is the functional trace, or after effect, from the pre- 

 ceding stimulation of the food. 



Vassiljev, P. N— Differentiation of Thermal Stimuli by the Dog. 



Warming a circumscribed region of the body to 47° C. has been made a conditioned 

 stimulus. Cooling to 0.2° C. was likewise tried. It is easy to get conditioned 

 reflexes to either of these stimuli, but the two together do not produce two distinct 



