26 ' H. HAYS BULLARD 



oxidizing compounds. Lipoids rendered insoluble by chromic 

 compounds stained with considerable intensity by Orange G but 

 could be stained with the anilin dyes only when the potassium 

 bichromate had been kept warm during the process of oxidation. 

 The hematoxylin lake in the case of the lipoids, did not follow 

 excepting after a mordant such as iron alum. It was also observed 

 that both albumino-lipoids (lecithalbumin) and mixtures of fatty 

 acid and albuminoids were precipitated by formalin in such a 

 way as to render the fatty substances practically insoluble in 

 ordinary fat solvents. For example, oleic acid in a precipitated 

 albuminous mixture was stained by various methods, even after 

 the action of alcohol and alcohol-ether for several days at a 

 temperature of 35°C. The methods of Altmann, Benda and 

 Weigert, although variously modified are, according to these 

 observers, based on the same chemical principles and give almost 

 identical results when applied to the mitochondria (Altmann's 

 granules or the true interstitial granules of this paper). After 

 an extended inquiry into the chemistry of the mitochondria, they 

 conclude that the granules contain a fatty body which is neither 

 a neutral fat nor a soap but is probably an unsaturated fatty acid, 

 absorbed by an albuminous granule or present in an albumino- 

 lipoid compound. 



If we assume with the authors just quoted and with Regaud 

 and Favre ('09) that the true interstitial granules are an albumino- 

 lipoid or a fatty-acid albuminous mixture, the action of formalin 

 in partially protecting them against fat solvents is explained in 

 that the albuminous component is coagulated by the formalin and 

 the fatty component is thus rendered less easily extractable. The 

 same assumption also permits us to explain the action upon 

 the granules of the methods of Altmann, Benda, Weigert and 

 Regaud. It would, of course, be a mistake to consider these 

 methods as specific for albumino-hpoids. They are of wide 

 application and do not afford distinctive evidence as to the chem- 

 ical nature of the substances stained. 



5. Results with acid fuchsin. Knoche ('09) obtained a micro- 

 chemical xanthoproteic reaction with the true interstitial granules 

 of Kolliker and belived that the proteid thus shown was an 



