In the second part published in 1674, the different kinds of tissue in the stem are discussed at greater length; here there is much that is really good, but at the same time much that is imperfect to an extent which cannot be attributed solely to the inferiority of his microscope. Very excellent is the way in which he endeavours to make out the more obvious anatomical relations of the rind, the wood, and the pith, and in the texture of the rind and the wood connects the longitudinal course of the vessels and woody fibre with the horizontal course of the medullary rays and the ‘silver-grain.’ The magnifying powers which he used must, to judge from his figures, have been very considerable; how much of what is imperfect in them is due to the indistinctness of the field of view, and how much to inaccurate observation, we cannot say. For instance, he sees the bordered pits in the wood of Conifers without perceiving the central pore, and represents them as coarse grains lying on the outside of the wood-cells; it was unfortunate for Malpighi, as for his successors, that the large vessels in the wood of dicotyledons, to which they gave most of their attention, are often filled with secondary tissue (thylosis), which Malpighi figures Tab. vi, fig. 21, but the true nature of which was not understood till 150 years later. Malpighi, like succeeding phytotomists till as late as 1830, lays great stress on the structure of the spiral vessels or tracheae, and mentions particularly that they are surrounded by a sheath of woody fibre; but he did not fall into the strange notions which Grew and other phytotomists entertained with regard to the nature of these vessels. We may at present omit the numerous remarks on assimilation and the movement of the sap; the descriptions and figures of the parts of buds and of the course of the bundles of vessels in different parts of plants, and especially the analyses of the flower and fruit and the examination of the seed and embryo, conducted with a carefulness remarkable for that time, deserve a fuller notice, but this would detain us too long from our main subject.