LECTURE IV. 



MALPIGHI AND THE PHYSIOLOGY OF GLANDS 

 AND TISSUES. 



The rapid development of mechanical and physical science 

 was not the only event taking place in the beginning of the 

 seventeenth century which profoundly influenced the progress 

 of physiology. The introduction of the microscope, though 

 acting in a different way, proved itself an aid of almost equal 

 importance to biological studies, though its effects did not 

 make themselves felt until more than half the century had 

 run its course. 



The anatomists of the sixteenth century, and of the early 

 part of the seventeenth century, were content like their fore- 

 fathers to carry on their studies with what we now call the 

 naked eye, unassisted by any optical instruments. Hence their 

 statements as to the finer structure of the various organs and 

 parts of the body were necessarily vague and incomplete. 

 They could tease certain parts more or less completely into 

 strands of greater or less thickness and hence could speak of 

 fibres and of fibrous structure. They recognized skins and 

 membranes of various thickness. They were able to distinguish 

 what we call fatty or adipose tissue by means of its gross 

 features. And they could follow out the blood vessels and later 

 on the lymphatic vessels until these were lost to view as minute 

 channels. Beyond this, they were content to speak of that 

 part of the substance of an organ which could not be split into 

 fibres, and into which the minute vessels seemed to disappear, 

 as ' parenchyma/ using the word introduced in ancient times by 

 Erasistratus, but no longer attaching to the word the original 



