INTRODUCTION OF THE MICROSCOPE 67 
vations successfully into periods earlier than about the 
twenty-four-hour stage of development. Two memoirs were 
written on this subject, both in 1672, which were published 
by the Royal Society of England under the titles De Forma- 
tione Pulli in Ovo and De Ovo Incubato. Of all Malpighi’s 
work, this has received the least attention from reviewers, 
but it is, for his time, a very remarkable achievement. No 
one can look over the ten folio plates without being impressed 
with the extent and accuracy of his observations. His 
sketches are of interest, not only to students of embryology, 
but also to educated people, to see how far observations 
regarding the development of animals had progressed in 1672. 
Further consideration of his position in embryology will be 
found in the chapter on the rise of that subject. 
Little is known regarding the form of microscope em- 
ployed by Malpighi. Doubtless, much of his work was done 
with a simple lens, since he speaks of examining the dried 
lungs with a microscope of a single lens against the hori- 
zontal sun; but he is also known to have observed with an 
instrument consisting of two lenses. 
Malpighi was a naturalist, but of a new type; he began to 
look below the surface, and essayed a deeper level of analysis 
in observing and describing the internal and minute structure 
of animals and plants, and when he took the further step of 
investigating their development he was anticipating the work 
of the nineteenth century. 
Jan SWAMMERDAM (1637-1680) 
Swammerdam was a different type of man—nervous, 
incisive, very intense, stubborn, and self-willed. Much of his 
character shows in the portrait by Rembrandt represented 
in Fig. 15. Although its authenticity has been questioned, 
it is the only known portrait of Swammerdam. 
