Being personally satisfied by clinical observations that certain of the acute insanities are toxic in their ætiology, it occurred to me that it might be possible to demonstrate the presence of the toxæmia by means of the delicate test of complement-deviation. I argued that if a toxin existed in the blood, it would probably be excreted in the urine, and that at certain stages of the disease process a corresponding immune body would be found in the serum. In a series of observations carried out on these lines, I used urines as the antigen, and serum as the immune body.

For some years, we have been engaged in an investigation into the mode of action of toxins upon the central nervous system, and up to the present time have devoted our attention exclusively to the question of the upward passage of bacterial poisons along the sheaths of peripheral nerves to the spinal cord and brain. Experiment has shown us that toxins readily travel upwards in the perineural lymphatics, in which they induce an inflammation whose phenomena vary with the intensity of the irritant; and that this is continued without interruption to the central nervous system, granted that the toxins gain that level. Continuity of extension is, therefore, an important feature of lymphogenous inflammation, and is as constant in the central as in the peripheral nervous system.

It is interesting at the present time to notice that disorders of the mind are being considered from a broader point of view. No longer is it reckoned sufficient to enumerate the psychic symptoms and to label the case accordingly. In the scientific journals it is not unusual to find the statement that a certain case does not fit into any division of our present-day classification. It is recognised that to describe a case as an atypical example of a disease is equivalent to saying that some factor has escaped our notice, or is one we cannot explain; that ætiology, from the psychogenic as well as the pathogenic point of view, must be considered, and that bodily and nervous symptoms may be as much a part of the illness as are the psychic; in fact, these last are often merely a symbol expressing some change in the function of an organ outside the brain.

Progressive general paralysis is remarkable for the frequency, multiplicity, and variety of its pupillary symptoms, which may often be evident even in the incipient stage of the disease.

Under the heading of “katatonia” are included certain peculiar states of stupor and excitement, which tend to alternate irregularly with one another. Thestuporose phase is characterised by increased muscular tension, or in some instances catalepsy, together with negativism, mutism, refusal of food, contrary acts, or not infrequently an increased suggestibility, as shown by echolalia or echopraxia. The prominent features of katatonic excitement are increased psycho-motor activity, attitudinizing, stereotyped movements and phrases, verbigeration, and senseless impulses. Various forms of convulsive attacks are motor phenomena which frequently occur during the course of the psychosis.

Cases of mental disease which give definite mental symptoms and physical signs of the condition recognised and at present called general paralysis of the insane, and which, moreover give a Wassermann reaction, seem to be invariably due to syphilis, and to contain in many cases spirochætes in the cerebral substance. Out of seven such cases of well-marked general paralysis, which on death were examined for spirochætes by Dr. McIntosh, six cases showed the presence of spirochætes. The seventh case was regarded as doubtful.