456 



SCIENCE PROGRESS. 



be a derivation of nucleic acid as it contains 0*54 per cent, 

 of phosphorus, but it was not obtainable from the thymus 

 gland, 1 nor from pure nucleic acid. 



From the first Baumann was inclined to the belief that 

 here was the active substance he was looking for ; this 

 opinion was, however, expressed with considerable reserve 

 until he had thoroughly tested the hypothesis by experiment ; 

 and in this part of the investigation he worked with Roos. 2 



They separated the substance by the use of either sul- 

 phuric or hydrochloric (10 per cent.) acid. It is insoluble in 

 these reagents, the other constituents of the gland being 

 soluble. It is thus extremely stable, and is moreover not 

 altered by heat. 



In the gland itself, thyro-iodin is, however, chiefly in 

 combination with the proteids. They found that the 

 proteids of the gland which can be dissolved out by saline 

 solution are an albumin and a globulin. 3 It is with the 

 albumin 4 that the greater part of the thyro-iodin is com- 

 bined ; the globulin contains a small quantity, and a third 

 portion is free, that is, not combined with proteid matter at 

 all. 



The following table gives some idea of the quantity of 

 iodine in the glands in human individuals. 



1 Later (Baumann, ibid., xxii., p. 1, 1S96) small quantities were obtained 

 from calf's thymus. 



2 Zeit. physio/. Chem., xxi. 481. 



3 For other work in the proteids of the thyroid see Gourlay, loc. cit. ; 

 Notkin, loc. cit. ; Bubnow, Zeit. physiol. Chem., viii., p. 1. The last observer 

 found three proteids, one a globulin. 



4 Query, Nucleo-albumin, W. D. H. 



