Pioneer Investigators of Photosynthesis. 193 
something for the benefit of the body; so likewise the skins of at 
least many plants are formed with several orifices or passports, 
either for the better avolation of superfluous sap, or for the 
admission of air.” 
On one of his plates Grew figures leaves of the pine and lily 
shewing what are undoubtedly stomata, although he does not give 
them that name, so that it must be admitted that Grew, a 
contemporary of Malpighi, not only was acquainted with the 
existence of such apertures but had some idea of their functions. 
It is scarcely fair to Grew’s memory, therefore, to say, as Sachs 
does, that he “ brought nothing to light that could assist the further 
development of the theory of nutrition.” 
Again, according to Sachs, Malpighi “ never succeeded in find¬ 
ing openings for the entrance of air in the roots or the leaves.” 
On the other hand, Malpighi’s description of his Plate XX runs as 
follows:—“ Among the vesicles and network of fibres in most 
leaves are distributed special little air bellows or gaps which pour 
out either air or moisture. These gaps are especially evident in the 
leaves of the Oleander; where each area has four to many pores or 
mouths, the whole surrounded by a margin bearing numerous 
hairs.” 
It is difficult to account for Sachs’s statement after reading 
these sentences, unless by assuming that he had never read Malpighi 
or that he trusted to some third party for his information as to 
Malpighi’s work. 
Malpighi’s views as to the part played by leaves in plant 
metabolism are thus summarised by Sachs : “ The liquids mingled 
together in their long passage through the network of fibres are 
changed in the leaves by the power of the sun’s rays and blended 
with the sap before contained in their cells, and thus a new combi¬ 
nation of the constituent parts is effected, transpiration proceeding 
at the same time.” The original, however, reads thus:—“Hence 
the active leaves seem to have been contrived by nature for the 
digestion of food which is their chief function, for that part of the 
nutrient sap which enters the roots from below and which is not 
diverted into the adjacent transverse branches, at length slowly 
reaches the leaves by way of their woody veins ; this is necessary 
so that the sap should linger in the adjacent vesicles and so be 
mingled with the sap already there and be fermented ; in this process 
the warmth of the surrounding atmosphere is of no little assistance, 
for it helps it the more readily to evaporate that which is of no 
