1908. | Minute Structure of the Nervous System. 435: 
produced by both Apathy’s and Cajal’s methods—even the preparations made 
by Apathy himself—but have never succeeded in discovering the reticula 
which they maintain as being present. 
Apathy, however, and his followers state that this is simply due to the 
staining not having been perfect. In that case all the stainings that have 
been submitted to our examination have been imperfect, including even 
Apithy’s own. | 
A scientific investigator is in duty bound to contine himself to describing 
what he really sees; he has no right to formulate theories on the basis of 
what he does not see, but only imagines and assumes that he may see. 
It is, of course, true that our power of sight is limited, and that even within 
the range of our vision there may be much of which we have no knowledge. 
We may form hypotheses and conceive probabilities concerning those regions 
which are invisible to us, but we must be very careful not to confuse 
those fancies with the exact results of science. Consequently, it will not 
be possible for scientific investigators to accept the existence of anastomosing 
reticula in the grey substance as a fact, and to build up scientific theories on 
that basis until reliable methods have proved it to be so. 
The sum of what has hitherto been shown by the investigations in this field 
is, according to my opinion, this only: That neurone fibrils are to be found 
in the nerve-cells and their processes, that they form in the cells abundant 
reticula, which are even plainly to be seen in some of the peripheral terminal 
organs, and that they do not anastomose outside the particular domains of the 
cell unit or neurones, 7.e. that they do not outside these form reticula but 
plevus. The several neurones are connected one with another per contigut- 
tatem, not per continuitatem.* Finally, there does not exist any certain proof 
that the fibrils constitute the sole conducting element. 
I know very well that there are instances described where there are 
observed anastomosing of nerve-cells, but these cases are really very few, and 
may be, if they are certain, considered as abnormal, and, at all events, very 
rare. The question as to the independence of the neurones one of another, or 
* During the preparation of this lecture for print I have received from the author, 
Dr. Em. Mencl, in Prag, a memoir on the “ Punktsubstanz of the Hirudinees.” His 
researches have led him to the same conclusions about its structure. ‘Ich habe,” he 
says at the end of the memoir, “das Verhalten der Neurofibrillen und der Zellauslaéufer 
wiederholt einer eingehenden Untersuchung unterworfen, natiirlich, wie erwahnt, an nach 
Apathy und Cajal behandeltem Material, hauptsichlich aber an den Cajal’schen Praparaten, 
wo die Reaction vollkommen gelungen war—und trotzdem habe ich nie irgendwelche 
Netze, ausser den intracellularen Kérbchen, gesehen, weder in den Verlauf der 
Ausliufer eingeschaltet, noch in der centralen Masse. In dieser Hinsicht kann ich direkt 
mit Retzius sagen: ‘ Auch bei den stirksten anwendbaren Vergriésserungen sah ich in 
der Punktsubstanz nie ein Netz, nur ein Geflecht, keine Anastomosen der Aste.’ ” 
