and there is, in addition, a 3-ellow matter. After comparing his re- sults with those obtained by Heeren, by an examination of the pro- ducts evolved by his erythrine in contact with air and "^"ith ammonia, and stating reasons for some changes in nomenclature, the author gives the chemical formulse resulting from his own analysis of these different substances.
His inquiries into the constitution of ordinary litmus, which form the last di^'ision of his subject, lead him to the conclusion that that substance contains the principles designated by him as Erythrolein, Erythrolitmine, Azolitmine, and Spaniolitmine ; and that the colour- ing constituents of litmus are, in their natural condition, red ; the blue substances being produced by combination with a base, which bases in that of commerce are lime, potass, and ammonia : and there is mixed up in the mass a considerable quantitj,^ of chalk and sand. The details of the analyses of these several substances, and the re- sulting chemical formulse representing their constitution, are then given.
The concluding section of the paper is occupied by an inquiry into the decoloration of the bodies which exist in archil and in Htmus. The latter of these, the author concludes, is reddened by acids, in consequence of their removing the loosely combined ammonia by which the blue colour is produced ; and the so-called hydrogen acids liberate the colouring matter by their combining with the alkali to form bodies (either chlorides or iodides), vrith which the colouring matter has no tendency to unite. Hence it appears that the redden- ing of litmus is no proof that chloride of hydrogen is an acid, and that the double decomposition which occurs is the same in principle, whether hydrogen or a fixed metal come into play. After detailiog the blanching effects of other deoxydizing agents on the colouring matter of litmus, and the action of chlorine on orceine and azolitmine, the author remarks, that in these actions chlorine is subjected to conditions different from those which determine the nature of the results with the generahty of organic bodies, and that the displace- ment of hydi"ogen, so marked in other cases, does not exist in the class of substances under consideration; but that, in reality, the products of the bleaching energy of chlorine resemble in constitution the compounds of chlorine which possess bleaching powers,
A paper was also read, entitled, " On the Corpuscles of the Blood." By Martin Barry, M.D., F.R.S.
The author in the course of his researches in Embryology, detailed in his " third series," observed that some of the corpuscles of the blood undergo progressive alterations in their structure. The cor- puscles so altered he believes to be of the same kind as those de- scribed by Professor Owen ; and having found that the alterations in question terminate in a separation of the corpuscles into globules, he thinks this fact confirms the idea of Professor Owen — that the blood- disc undergoes spontaneous subdivision. Tlie author farther observed that the corpuscles of the blood, in certain altered states, undergo rapid and incessant changes of form, which cannot be traced
