424 INTRODUCTION TO CYTOLOGY 



plant with that of a basket, also with "fine bone-lace, when the women 

 are working it upon the cushion." 



Marcello Malpighi (1628-1694), an Italian physiologist and professor 

 of medicine, is best known for his important pioneer work in anatomy and 

 embryology. Most of his observations on plants were included in his 

 Anatome Plantarum (1675) and had to do largely with the various kinds of 

 elements making up the body of the vascular plant. A foreshadowing of 

 the cell theory is seen in his remarks concerning the importance of the 

 " utriculi " in the structure of the body. At Pisa, Malpighi was associated 

 with G. A. Borelli, w^ho was one of the first to use the microscope on the 

 tissues of higher animals. 



Antoni van Leeuwenhoek (1632-1723) of Delft is remembered for his 

 pioneer researches in the field of microscopy. He constructed a number 

 of simple lenses of high power, and with these he was able to see for the 

 first time certain Protozoa, bacteria, and other minute forms of life. 

 In the course of his investigations he observed the cells ("globules") 

 in the tissues of higher organisms. 



Preformation and Epigenesis. — After the death of the above named 

 observers there ensued a period during which the actual investigation 

 of the structure of organisms remained practically at a standstill. There 

 was, however, considerable indulgence in speculation; this should be 

 recorded here, not because it can be regarded as scientific cytology, but 

 because of the influence it exerted upon the formulation of many cyto- 

 logical problems in later years. Such speculation resulted in the division 

 of the biologists of the day into two schools, the main controversy being 

 over the manner in which the embryo develops from the egg. The two 

 theories formulated in answer to this question were called the 'preformation 

 theory and the theory of epigenesisr 



According to the preformation theory, the basis for which was laid 

 in the seventeenth century works of Swammerdam, Malpighi, and van 

 Leeuwenhoek, the egg contains a fully formed miniature individual, which 

 simply unfolds and enlarges as development proceeds. Because of this 

 unfolding, the theory was also known as the "theory of evolution," an 

 expression which has a quite different connotation today. In the 

 eighteenth century the preformation idea was carried to an absurd 

 extreme by Bonnet (1720-1793) and others, who argued that if the egg 

 contains the complete new individual, the latter must in turn contain 

 the eggs and individuals of all future generations successively encased 

 within it, like an infinite series of boxes one within another. The pre- 

 formationists soon became separated into two groups: the spermists, or 

 animalculists, and the ovists. By the former the new individual was 

 supposed to be encased in the spermatozoon, and figures were actually 



2 See the account by Cole (1930). 



