32 PARALYTIC AND ANTILYTIC SECRETION. [BOOK II. 



Characters of so-called ' Paralytic ' Submaxillary Saliva, 

 ' Antilytic ' secretion. 



It was pointed out by Claude Bernard 1 that after the nervous 

 influence had been cut off from the submaxillary gland, a very watery 

 saliva is continuously poured out. This so-called ' paralytic ' secretion 

 occurs if the chorda tympani alone has been divided. 



Heidenhain 2 in a most interesting investigation on this subject 

 discovered the very remarkable fact that when the chorda tympani is 

 divided there follows a continuous secretion from both submaxillary 

 glands, although the secretion is more abundant on the side on which 

 the section has been made. Whilst the term ' paralytic ' may be 

 applied to the secretion flowing from the gland whose connexion with 

 the nerve centres has been severed, we may in accordance with 

 Langley's suggestion 3 call the secretion which is set up on the 

 opposite side of the body the anti-paralytic or ' antilytic ' secretion. 



Langley's researches, which have corroborated and extended our 

 knowledge of the facts discovered by Heidenhain, seem to render it 

 certain that the flow of saliva both paralytic and antilytic which 

 follows section of the chorda tympani on one side, is primarily due 

 to a change set up in the secretory centres which are situated in the 

 brain and which result in a continuous stimulation of both glands, the 

 stimuli, in the case of the paralytic flow, travelling along sympathetic 

 fibres, whilst in the case of the antilytic secretion they presumably 

 pursue both courses open to them. The change in the nerve centres 

 brought about by section of the chorda appears to be of the nature of 

 an increase of their excitability ; this is supported by the fact that in 

 the altered condition induced by nerve section, a state of dys- 

 pnoea induces an increase in the flow of saliva not observed when 

 the nerves are intact. 



The fact, however, that a paralytic secretion persists even after 

 the submaxillary gland has been entirely severed from its connection 

 with the central nervous system negatives the idea that the secretion 

 is entirely dependent upon it, and the hypothesis which has been 

 framed in order to account for the facts is that the paralytic secretion, 

 in its later stages, depends upon an excitation of the local nerve 

 centres situated in the gland itself. 



The hypothesis is supported by the fact discovered by Vulpian 4 

 that pilocarpin causes a secretion from the, submaxillary gland four- 

 teen days after section of the chorda and sympathetic nerves, as 

 well as that apncea. dyspnoea and anaesthetics affect the secretion 



1 Bernard, Journal de V Anatomic et de la Physiologic, Vol. i. (1864), p. 507. 



2 Heidenhain, 'Beitrage zur Lehre von der Speichelsecretion. ' Studien des phys. 

 Instituts zu Breslau, Heft iv. (1868), p. 73. 



3 J. N. Langley, 'On the Physiology of the Salivary Secretion.' Part m. 'The 

 Paralytic Secretion of Saliva.' Journal of Physiology, Vol. vi. p. 71. 



4 Vulpian, Comptes Eendus, T. 87 (1878), p. 350. 



