HISTORICAL INVESTIGATION. 15 



The attempts made by the early microscopic observers to de- 

 termine ultimate structure, were in general of little value, 

 partly on account of the imperfections in the instruments em- 

 ployed, and partly from the mistakes they made in judging of 

 the novel appearances presented to their view. This last cause 

 of error still exists, and inexperienced observers may very 

 readily be led astray. By such, a fibre of cotton upon the 

 stage of the microscope, moving in obedience to the hygrometric 

 influence of the breath or of a moist atmosphere, might be re- 

 garded as a living animal ; or the influence of various reagents 

 on pus, mucus, blood, or other matters, might lead to error. 

 This last was the case with the celebrated Borelli, who was 

 the first to apply the microscope to the examination of struc- 

 ture. 



Borelli was born in 1608, and lectured as professor in the 

 University of Pisa in 1656. In his day a general idea pre- 

 vailed, that diseases were occasioned by animalculse existing in 

 the animal tissues and fluids. An examination of abnormal 

 fluids with the microscope favored this idea, as the globules 

 were immediately taken for living beings. Borelli described 

 the pus globules as animalcules, and even says he has seen them 

 delivering their eggs. It will be seen that this was a very 

 natural mistake, when we remember that these globules contain 

 several minute granules, which make their escape when the 

 external envelope is broken or dissolved. In this way we 

 often find the germs of truth in the curious speculations of the 

 early microscopists. 



Malpighi was the first to witness the most beautiful sight 

 which the microscope can reveal, the actual circulation of the 

 blood, thereby demonstrating the reasoning of Harvey to be 

 true. The first work he published, in 1661, comprises his 

 microscopic observations relative to the structure of the lungs. 

 Between this period and 1665, he published other tracts on the 



