CHEMICAL PREPARATIONS AND DRUGS. 111 
of the pituitary membrane of patients, vibrionidz and staphylococci, and these were 
proclaimed by their discoverers as the cause of hay-fever, although apparently this 
theory was not put to the test experimentally by infecting sensitive mucous membranes 
with bacteria-cultures. Other authors, again, traced the origin of the disease to certain 
odoriferous substances or other volatile emanations exhaled by plants at flowering-time. 
The researches of Dunbar, in collaboration with Prausnitz, Kammann, Weichardt, 
_ Kattein, Liefmann, Liibbert, and others, which were commenced about the year 1902, 
have completely cleared up these mutually contradictory and partly unverified theories. 
It is impossible in this place to enter at length into an exposition of the many 
painstaking separate investigations of the above-named and other enquirers in this 
sphere of research; for such particulars we must refer to our previous Reports, but 
we may summarise below the outcome of their research in three general rules laid 
down by Prausnitz: — 
1. The pollens of graminaceous plants only set up the symptoms of hay-fever in — 
subjects predisposed to the disease; not in normal subjects. 
2. During the hay-fever season the pollens of graminaceous plants are present in 
the atmosphere in sufficient proportions to set up attacks of hay-fever. 
3. The variations in the proportion of pollen of graminaceous plants present in 
the atmosphere, generally go parallel with the degree of virulence of the 
attacks of hay-fever. 
The question in what manner the pollens which cause hay-fever act upon sensitive 
mucous membranes led to further thoroughgoing investigations. The exterior form of 
the pollens differs greatly; those of graminaceous plants are smooth and round or 
oval-shaped, those of the Ambrosia- and Solidago-species, which in America provoke 
the autumnal catarrh described above, have round or pointed protuberances. It was 
therefore impossible to connect the exterior shape of the pollens with their property 
of provoking hay-fever, and, the theory of mechanical causation being thus overthrown, 
there only remained the possibility of chemical processes as the determining cause 
of the pathological irritation. These conditions were thoroughly explored by Kammann 
with the pollen of rye. A chemical investigation of the constitution of this pollen 
gave the following results: water 10,2 p.c., ash 3,4 p.c., organic substances 86,4 p.c. 
Of the last-named, 3 p.c. were waxy or fatty bodies soluble in alcohol and ether, 
25 p.c. hydrocarbons (starch), 18 p.c. nitrogenous bodies of a non-albuminous character, 
and 40 p.c. aibuminous bodies. The pollen was ground to an impalpable powder in 
a mortar and extracted with a 5p.c. solution of common salt for from 5 to 10 hours 
at a temperature of 37°, with the addition of 0,5 p.c. of phenol. The empty bags 
of the pollen and the rods of starch remained undissolved by this treatment. It may 
be that these were the bodies which earlier investigators mistook for vibrionidz. 
When thoroughly washed out and tested on hay-fever patients, they proved to be inert, 
as also did the pollen-extract which was soluble in ether and alcohol; the untenable 
character of the theories of the activity of “vibrionidz” and odiferous substances being 
thus clearly established. On the other hand it was found that the solution, when 
separated from the undissolved portions by centrifugal action, had a pronounced effect 
upon sensitive mucous membranes. The albuminous bodies were now precipitated by 
adding a large excess of alcohol to the clear toxic solution, and these bodies were 
found to exhibit the irritant properties of the pollen in an increased degree. By re-dis- 
solution and fractionated precipitation by means of the familiar salts employed in 
separating albumins (ammonium and magnesium sulphates), it was further shown that 
the body which sets up hay-fever is attached to the albumin-fraction of the crude 
