176 



Dr. F. Medigreceanu. On the 



[Nov. 21, 



seemed of interest to study its occurrence and quantitative distribution in 

 tumours. The transplantable tumours (mouse, rat, dog) were chosen for the 

 purpose. These kinds of tumours are at present the best known as regards 

 their biological and morphological properties, and the most suitable for an 

 exact and rapid orientation. 



The tumour strains analysed belong to both the principal morphological 

 groups — carcinoma and sarcoma. Each strain shows different morphological 

 and biological properties.* 



Technic. 



As already mentioned in the introductory part, the estimation of manganese 

 was made by Bertrand's colorimetric method. It consists essentially in 

 converting the manganese present in the sulphate ash of the organic substance 

 into permanganic acid, in oxidising the ash dissolved in concentrated nitric 

 acid with potassium persulphate in the presence of silver nitrate, and in 

 comparing the intensity of its rose-pink to violet colour with the colour of 

 standard solutions of the same acid prepared in a similar way. The details 

 of the method were followed exactly as given by Bertrand and Medigreceanu.f 



Of the tumour tissue to be analysed quantities not exceeding 100 grm. were 

 first dried at 100° C. and then incinerated at the lowest possible temperature, 

 using sulphuric acid for the destruction of the final traces of carbon. The 

 sulphate ash was then dissolved in concentrated hydrochloric acid, again 

 treated with a little sulphuric acid, and finally heated until the appearance 

 of white fumes of sulphuric acid denoted the absence of hydrochloric acid. 

 The residue was then dissolved in 10 c.c. of 25-per-cent. nitric acid, and if 

 necessary the undissolved part of the ash allowed to precipitate. A few 

 drops of 10-per-cent. silver nitrate was then added to the clear solution, the 

 tube warmed, and its contents oxidised with a few decigrams of potassium 

 persulphate. 



The greatest care was always taken to avoid introducing impurities 

 containing manganese into the samples for analysis, and pure reagents were 

 used throughout. 



It may also be mentioned that the small quantities of blood contained in 

 the tumours do not influence the analytical results, for it was found that 

 25 grm. of mouse blood treated in the same way did not show any visible 

 trace of manganese. This fact fully agrees with the previous findings of 

 Bertrand and Medigreceanu, who observed only traces of manganese in larger 



* Full details on the tumours analysed may be found in the ' Fourth Scientific 

 Keport on the Investigations of the Imperial Cancer Eesearch Fund,' London, 1911 , 

 Taylor and Francis. 



t 1 Bull. Soc. Chim. France,' 1912, Ser. 4, vol. 11-12, p. 656. 



