Abstract
Conclusion
These facts definitely prove in our minds that the bloody tears contain no erythrocytes, and the red pigment in chromo-dacryorrhesis is not hemoglobin. The minute pink corpuscular bodies are in reality colorless fatty globules, tinged red by the pigment that surrounds them. In other words, chromodacryorrhesis is not a dia-pedesis of erythrocytes, and the tears do not even contain hemoglobin. It is really a most surprising fact for those who are familiar with the phenomenon of chromodacryorrhea that such obviously bloody fluid coming out of mammalian tissue does not contain any blood.
On the other hand, these findings now seem to help explain many puzzling facts. One of us (with Stix) 1 found that dacryorrhetin causes bloody tear production only in rats (with occasional exceptions with mice), milky tears in guinea pigs, rabbits and mice, and clear tears in cats and dogs. Just why rats alone should shed bloody tears has been one of the perplexing problems. On the basis of the above findings, we can safely attribute the cause of chromodacryor-rhea to a peculiarity of rats in respect to Harder's glands.
Derrien and Turchini 6 describe a substance, a porphyrine, in Har-der's glands of rats and in lesser amount in those of mice. One wonders if this porphyrine is identical with the bloody pigments of the tears, or gives rise to it.
Preliminary experiments (by B) suggest that these two are probably identical as judged by ultraviolet fluorescence and the solubility characteristics of pigments as well as of their salts. Just exactly what the chemical nature of this pigment in the tears is and what the function of dacryorrhesis is, is another problem.
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