THE HISTORY OF THE SUBJECT 3 



of the preceding period of thought. When the ideas of Glisson 

 are isolated from the wilderness of scholastic phraseology, the 

 system is somewhat as follows. The basis of all existence, 

 "substance," has according to him two general properties, its 

 "fundamental subsistence," that is, the essence of its being, and 

 its "energetic subsistence," that is, the essence of its activity. To 

 these are added the properties possessed in specific cases, that is, 

 its "additional subsistence." The energetic subsistence forms the 

 basis of all life. Life is therefore present not only in organic 

 nature, but in all nature which is characterized by the union of 

 the general energetic subsistence with the special additional sub- 

 sistence of an animal and vegetable nature. In other forms of 

 life in nature the energetic subsistence is combined with other 

 special forms of the additional subsistence. The universal 

 essence of all life, that is the energetic subsistence, has only three 

 fundamental faculties : the "appetitiva," the "perceptiva" and the 

 "motiva." The modus is the result of a "perceptio," but the 

 "perceptio" is not thinkable unless the object has the "appetitus" 

 to receive the external influence. Glisson's doctrine of irritability 

 is based on this conception, which he develops in a second work 

 already begun before the "Tractatus de natura substantice," but 

 not finished until later and only published after his death. In 

 this "Tractatus de ventriculo et intestinis,"^ Glisson dwells in 

 detail on the physiological properties of animal structures and 

 develops for the first time his conception of irritability in the 

 chapter "De irritabilitate fibrarum." The "irritability" manifests 

 itself in the appearance of the alteration of movement, which is 

 brought about by external influences on the animal structure, for : 

 "Motiva fibrarum facultas nisi irritabilis foret, vel, perpetuo 

 quiesceret, vel perpetuo idem ageret." The fundamental factor of 

 this irritability Glisson attributes to the "perceptio," which he dis- 

 tinguishes as a "perceptio naturalis, sensitiva and animalis." 

 The want of clearness produced here by Glisson's artificial distinc- 

 tions and mode of expression is in part removed if we endeavor 



1 Franciscus Glissonius: "Tractatus de ventriculo et intestinis cui prxmittitur alius 

 de partibus continentibus in genere et in specie de lis abdominis." Amstelodami M D 

 C L XXVII. 



