Page:Popular Science Monthly Volume 69.djvu/18

14 within the last twenty-five years, the best known and probably the most important, certainly the most spectacular and unforeseen, is the revelation of the structure of the nervous system and of the relation of the nerve cells to one another. This wonderful achievement has been due chiefly to the introduction of a single new method, named after its inventor Golgi, one of those brilliant modern men who prove that genius is still the gift of the Italian race. He was born at Corteno on the ninth of July, 1843. The method was first described in 1875 in an article on the fine structure of the olfactory bulbs. The method was so radically different from anything known at that time that it was treated with scornful incredulity, and no attention was paid to the new invention which was destined to revolutionize our knowledge until it was introduced in Germany by Professor Kölliker in 1887. This marvelous method has been found to work best with embryos and has enabled us to trace out the form, including their ramifications, of the nerve cells and neuroglia cells of the brain and spinal cord throughout their whole period of development. As you know, all our contemporary teaching in regard to the structure and functions of the central nervous system, our conceptions of the nervous mechanism within the central nervous system and in the ganglia, are based upon the results obtained through the application of Golgi's method by embryologists. It is pleasant to note that in 1903 the completion of twenty-five years of teaching, and, by a happy coincidence, the anniversary of his silver wedding, were celebrated by Professor Golgi's pupils by the publication of his complete works, 'Opera Omnia,' in three magnificent quarto volumes. Copies of this publication ought to be in every pathological and histological laboratory in the world. Indeed, every text-book of anatomy, embryology or pathology published now-a-days is a memorial of Professor Golgi, for they are all abundantly supplied with figures of Golgi preparations. We may see in this history an illustration both of the value of the embryological data and also of the almost" creative power of a new method.

Degeneration has long been regarded as essentially a pathological process. This is the view which we have inherited. Nevertheless it is incorrect, as has been demonstrated by the more exact study of normal cytomorphosis during recent years. We now know that degeneration is to be looked upon as a normal end to a complete cytomorphic cycle. Instances of normal degeneration have long been familiar to us. Our mistake has been in overlooking their interpretation, their significance as part of the normal life. Thus the horny layer of the skin is made up of degenerated cells. Cartilage when it is replaced by bone undergoes a normal degeneration. In short, we must regard pathological degeneration very much as we regard those plants which we call weeds, things which are growing