[Reprinted from The Medical News, March'io, 1894.] 
THE THERAPEUTIC USES OF THE SALTS OF 
CESIUM AND RUBIDIUM. 
By THEODORE W. SCHAEFER, M.D , 
OF KANSAS CITY, MO. 
In the years i860 and 1861 Bunsen and Kirchhoff, by 
means of their memorable four-prism'' spectroscope 
(which, by the way, was on exhibition at [the recent 
World’s Fair in Chicago), discovered the two alkali- 
metals, cesium and rubidium, while examining the 
waters of Duerkheim, Germany. Together with others, 
they succeeded in finding these alkali-metals in many 
waters, soils, plants, and in the animal system. Fur- 
ther spectrum observations showed even traces of rubid- 
ium and cesium in the blood of man, demonstrating the 
fact that they are widely diffused in Nature, although in 
minute quantities. 
Lucanus experimented with cesium and rubidium 
upon the growth of plants and claimed that the latter do 
not absorb the salts of these metals and that they act 
inimically upon them, but repeated experiments in recent 
years have shown the fallacy of his claims. In 1864 
Claude Bernard, the celebrated French physiologist, 
experimented with the salts of rubidium and demon- 
strated that they are less toxic to the cardiac apparatus 
than the preparations of potassium. 
Cesium is the most electro-positive of the elements. 
Rubidium, its partner, comes next. Cesium and fluorin 
should be considered as chemic “ ideals,” because of 
their prominent chemic and physical characteristics. 2 
Fluorin, as I have elsewhere pointed out, is the most 
electro-negative member of the elements, whilst cesium 
is the most electro-positive. The chemic, physical, and 
physiologic activities of cesium and rubidium rank higher 
than those of potassium, sodium, or the other members 
of the alkali-group. The presence of cesium and 
rubidium in plants and in the animal organism must 
certainly serve a purpose. Just as fluorin, in its electro- 
negative functions and chemic affinities, is an inherently 
associated member of the halogens, so does cesium 
behave as a member of the alkali-metals in its chemic 
functions and electro-positive activity. The researches 
of physiologic chemistry teach that substances having 
allied properties must have also analogous actions upon 
the organism, and the difference of their modes of action 
can be explained on chemic principles. 
My uncle, Dr. Edward Wernigk, once assistant of 
Prof. Bunsen, experimented as early as 1876 with 
cesium and rubidium upon his body. He again repeated 
these experiments on his own person in 1880, using 
cesium bitartrate. He believed that cesium and its salts 
acted favorably upon his heart, as he was suffering from 
a cardiac neurosis. It also acted favorably upon the 
generative organs. He assured me that the salts of 
rubidium and cesium possess the same therapeutic 
effects as the other alkali-salts. In experimenting upon 
his person he always took the cesium salts in smaller 
quantities than when he was taking the other alkali- 
salts internally. Thirteen years ago cesium salts were 
very expensive chemicals to experiment with, and as 
his deductions were mostly speculative he was not pre- 
pared to publish his results in scientific journals. I 
have an unpublished manuscript, written in 1881, in 
which I have noted the following in regard to cesium 
and rubidium : 
“ Since cesium appears to possess the most electro- 
positive character of the elements, one would rationally 3 
suppose that it might play an important function in the 
animal and vegetable kingdoms. So is it the case with 
rubidium, the next electro-positive element in rank. It 
is not difficult to understand that cesium and rubidium, 
on account of their very high electro-positive nature, 
probably perform the functional activities of the alkalies 
in a higher degree. Cesium is reputed to operate toxi- 
cally upon the nerves of the heart, and the same is 
stated of rubidium. It is a great question if this be 
really true. It is more reasonable to suppose that the 
elements cesium and rubidium, in combination with the 
halogens, will perform their chemic and physical func- 
tions much more conspicuously in the system than the 
lower electro-positive members of the series.” 
Dr. Wernigk always used cesium bitartrate in small 
doses, beginning with of a grain and increasing to 
5 grains three times daily. I have used the bromid and 
bitartrate of rubidium when experimenting on myself in 
doses of from 3 to 5 grains three times daily. I used 
rubidium bromid to alleviate nervous palpitation of the 
heart. I would have used cesium bromid, but was pre- 
vented on account of the high price of the salts of 
cesium. 
As soon as the exorbitant market price of the salts of 
'cesium and rubidium is reduced, there is no doubt that 
they will often be substituted for potassium or sodium 
salts. Experience will also doubtless teach that they 
can be given in larger doses. 
Cesium is the ideal alkali-metal. It was the first ele- 
ment discovered by means of spectrum analysis. Chem- 
ically it is the king of the alkali-metals, being the most 
electro positive member of the elements and outstripping 
them all in electrolytic conductivity. Metaphorically 
speaking, it stands with rubidium in the same relation- 
ship as gold does to silver.