225 



porphyrin soluticms just past tlu' kä linc. and a second just past tlie 

 thalliiun line, I was therefore induccd to ri'peat tliese expcriments 

 with phvlliiporpli3-rin and again fduml the twn bands in oxactly 

 the same position. 



Mr. SchuiK'k had also tlic kindness to examine his old plates 

 of the ])hylli)p(irphyrin spectruni and found that the two band.s are 

 présent, but they were not inentioned in his very interestinjf paper 

 on the subject. Concerning the double band past the k[i line I liave 

 been unable to find a split even at considérable dilution, but it is quite 

 possible that I have not been lucky enougli to just hit the correct 

 concentration. The second band in the more refrangible part of the 

 spectrum (past the thalliuni line) may be also fonn<l in the haema- 

 toporphyrin spectrum, but bnth bands are moved somewliat towards 

 the red end of the spectrum. 



A cid solutions. As will be seen fnjm the reproduction of 

 a photo taken on a spectrum plate of Messrs. Cadett and Neal. the 

 spectra caused by acid solutions of mesoporphj'rin and phyllopor- 

 phyrin are identical. 



The acid liaematoporphyrin solutions cause, as is well known. 

 also three bands. which are shifted slightly towards the red end. 



In more concentrated acid solutions all the three porphyrins 

 cause, in addition to the bands shown by the photo, two very faint 

 bands in front of F. 



The ab.sorption in the ultraviolet part is characterised in the 

 case of liaematoporphyrin and phylloporphyrin. as shown by C. A. 

 Schunck, by a band past the k|i line. Mesoporphyrin shows exactly 

 the same band as phylloporphyrin. 



The action o f b r o m i n e on m e s o p o r p h y r i n a n d 

 phy llu |)o rph y r in. The study of the behaviour of mesopor- 

 phyrin tnwards bromine had a special interest. As is well known, 

 the chi(>f différence which characterises haematopcjrphyrin as com- 

 pared with phylloporphyrin is that the product obtained by the 

 action of brominc on the former lacks an absorption band in the 

 extreme visible red. It has been shown that mesoporphyrin resem- 

 bles phylloporphyrin still more closely than haematoporphyrin. 

 and it could therefore have been expected that „bromomesoporphy- 

 rin" would sliow the additional band which we missed in the spec- 

 trum of .,ljr.imiilia(>inatii|)i'rpliyrin". These expectati(jiis have indeed 

 been justitied. as will he seen fVoni the appended drawing showing 



1* 



