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Hartshorne. ] u 7 2 [Oct. 20, 
tact, he was obliged to forego on account of his failure in health, which, 
after great suffering for several months, ended his life January 15, 1871. 
In private practice, Dr. Rhoads was rapidly gaining the confidence and 
success which his skill and acquirement deserved ; as well as the warm 
and grateful attachment of many families, —which remains in commemora- 
tion of his virtues, more faithful than any eulogy, and more endur- 
ing than any monument. He was elected to membership, besides the 
Philosophical Society, in the Philadelphia College of Physicians, of which 
he was Recording Secretary, the Academy of Natural Sciences, and the 
Pathological Society. To the proceedings of the latter he contributed a 
number of papers. He wrote for the American Journal of the Medical 
Sciences several reviews, showing a quick critical apprehension, a large 
acquaintance with medical science and literature, and an excellent com- 
mand of language. He assisted Dr. J. F. Meigs in the preparation of an 
elaborate paper, published in the first volume of the Pennsylvania Hos- 
pital Reports, 1868, on ‘The Morphological Changes of the Blood in 
Malarial Fever.”’ With Dr. W. Pepper, he contributed to the same vol- 
ume the results of an extended inquiry into the “ Kluorescence of the 
Tissues of the Human Body, especially in connection with Malarial 
disease and the action of Quinia.’’? The scientific spirit which animated 
all his professional labors, and which he brought to the investigation of 
the great problems of Pathology and therapeutics, thus elevating the vo- 
cation of the physician far above routine, was well exemplified in this 
paper. Its preparation was suggested by the remarkable observation of 
Bence Jones, by whom a fluorescence resembling closely that of a solution 
of quinine was found to eccur in solutions of the tissues of animals which 
had taken none of that substance. A peculiar fluorescent organic princi- 
ple was here inferred to be a normal constituent of the animal body ; and 
to this Bence Jones applied the name of ‘ Animal Quinoidine.”’ It was 
not an irrational hypothesis, that the systemic effects of the malarial 
poison may be attended by an injurious deficiency of this material ; and 
that quinine, or the other extractives of Peruvian bark, may be remedial 
for the disease, by supplying the system with its equivalent. 
Drs. Rhoads and Pepper undertook first, to ascertain whether, by 
chemical and spectroscopic analysis, there could be shown to be a marked 
diminution in the amount of animal quinoidine in the body under the in- 
fluence of malarial disease. They also gave attention to the effect upon 
the animal fluorescence produced by the treatment of the attack by sul- 
phate of cinchonia. The interesting result was arrived at by a series of 
careful and exact determinations, that there is, uniformly, a close con- 
nection between malarial disease and the diminution of ‘animal quinoi- 
dine ;”’ and that this connection is apparent, not only in the presence of a 
fully developed paroxysm of fever, but also when the system is more in- 
sidiously, though often very seriously, affected by the morbid cause. 
The same exact inquiry into evidence, with the aim to discover and es- 
tablish truth, was applied by Dr. Rhoads in his consideration, both theo- 
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