388 THE DUCTLESS GLANDS 



exist side by side with the diaphysis described by Favaro, and 

 it is connected with a very distinct bundle of nerve fibres. 



This structure, which the author 

 calls " corpus praepineale," ap- 

 pears to reach its maximum 

 development in the later foetal 

 stages and the earlier period of 

 extra-uterine life. After this it 

 becomes reduced, and seems to 

 be absent in the adult. 



Costantini calls special atten- 

 tion to the granular nature of 



FIG. 105. A small portion of -in j i j 



the pineal gland of the cat, as the pineal cells, and concludes 

 seen under a high power of that the pineal body is an in- 

 MlThrpTn.) <DraWn ^ ternally secreting gland. Similar 



conclusions have been reached 



by Galasescu and Urechia, who called special attention to the 



oxyphile cells of the gland. 



Physiological Experiments upon the Pineal Body 



1 . Injection of Extracts of the Pineal Body 



The first experiments in this direction were made by Howell 

 in 1898. This author reports that glycerine extracts of the 

 body produce sometimes a slight, sometimes a marked fall of 

 blood-pressure. This observation has, of course, little or no 

 bearing on the function of the organ. (See discussion in 

 Chapter III.) 



Cyon in 1903 made extracts from the pineal bodies of the ox 

 and sheep, and tested their effects upon the heart and blood- 

 vessels on intravenous injection. There was no effect upon the 

 blood-pressure, probably because the dose was not large 

 enough. The number of heart-beats was, however, increased, 

 while the excursion was diminished. This is an effect similar 

 to that obtained by stimulation of the true accelerator nerves. 

 Such are the effects of small doses. With larger doses the 

 heart-beats become stronger and less frequent, and also 

 irregular. The pulsus bigeminus and the pulsus trigeminus 

 are frequently observed ; there is a disturbance of the harmoni- 

 ous co-operation of the inhibitory and the accelerator cardiac 

 nerves. With still larger doses there may be a fall of blood- 



