300 Royal Society :— Dr. Martin Barry 



azoerythrine ; of each of the two former there exist two modifications, 

 and there is, in addition, a yellow 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 with ammonia, 

 and stating reasons for some changes in nomenclature, the author 

 gives the chemical formulae resulting from his own analysis of these 

 different substances. 



His inquiries into the constitution of ordinary litmus, which form 

 the last division 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, m 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 quantity of chalk and sand. 

 The details of the analyses of these several substances, and the re- 

 sulting chemical formulae 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 litmus. 

 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), with 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 detailing 

 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 generality of organic bodies, and that the displace- 

 ment of hydrogen, 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, U 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. The author farther 

 observed, that the corpuscles of the blood, in certain altered states, 

 undergo rapid and incessant changes of form, which cannot be traced 



