PAWLOWS THEORY OF THE FUNCTION OF THE 

 CENTRAL NERVOUS SYSTEM AND A DIGEST OF 

 SOME OF THE MORE RECENT CONTRIBU- 

 TIONS TO THIS SUBJECT FROM 

 PAWLOWS LABORATORY 



SERGIUS MORGULIS 



Nearly ten years ago, Professor Pawlow inaugurated the analy- 

 tical method 1 for the investigation of the function of the nervous 



1 It will not be amiss, perhaps, to lay special stress on the strictly analytical 

 character of Pawlow's researches. His point of view is thoroughly materialistic, 

 and his terminology and methodology alike are most consistently objective. The 

 results obtained in his laboratory are, therefore, of extraordinary importance. I 

 am greatly obliged to Professor T. B. Robertson of the University of California, who 

 recently inspected Pawlow's laboratory, for some additional points concerning 

 the experimental procedure adhered to in the conditioned reflex work of which I 

 had no information from reading the literature. 



The construction of the laboratory is such that no vibrations of any kind can 

 affect it. The animals, during the experiment, are placed in separate compartments 

 enclosed by walls composed of several layers which make them absolutely vibra- 

 tion-proof and sound-proof. The experimenter is invariably outside the com- 

 partment and the entire experiment is conducted by automatic arrangements. 

 The stimuli are produced from the outside and the food is also dropped into a dish 

 in front of the animal from a suspended box which opens and closes by a com- 

 pressed air apparatus operated by the experimenter. 



The salivary flow, recorded in drops, is in reality measured most accurately. 

 This is done by either of two methods. A manometer, several feet long, is con- 

 nected to a small air chamber into which the saliva flows and the amount is meas- 

 ured by the displacement of the meniscus. The manometer is calibrated with 

 drops of a standard size, causing a displacement so extensive as to enable very pre- 

 cise measurement. The other method consists of an electrical device. The saliva 

 flows through a capillary tube and the drop formed at the outgoing end of the tube, 

 as it falls through a somewhat wider channel, strikes two platinum wires making 

 a contact which is marked on a smoked drum. The time is likewise recorded auto- 

 matically. In either case the recording apparatus is outside and is inspected with- 

 out disturbing the animal. 



Considering the ideal experimental conditions which are observed by Pawlow 

 and are the direct outcome of his mechanistic-analytical point of view the follow- 

 ing statement which he made at a scientific meeting in Moscow and pointed against 

 our students of animal behavior may not seem wholly unjust. He said — " The 

 lion's share of these investigations is at present contributed by the new residence 

 of science — North America. But in these American investigations of the behavior 

 of higher organisms there is still, to my mind, a conspicuous flaw hindering the 

 success of the undertaking which will be unquestionably rectified sooner or later. 

 This is the use of psychological conceptions and classifications in investigations 

 which are truly objective. Hence comes the frequent aimlessness of their complex 

 methods and the invariable lack of cohesion and system in their material which is 

 without a well planned foundation." 



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