IIO ( iiuoMorAKors HACTKKIA 



text-books to Bacillus synxanthus. It is desirable that the study of the 

 organisms of yellow milk should be taken up anew, since Schroeter's investigations 

 were not performed upon pure cultures in the present acceptance of the term. 



With the species hitherto described (Bacterium eyregium, B. chrysogloia, 

 Stapt/lo<'f>cc,i8 pyogenes aureus, B. 9y*OMH&*m) there can be associated a 

 number of others, equally characterised by the faculty of producing yellow 

 colouring matters. Of these, mention will here be made merely of the Micro- 

 coccus ochroUucus, discovered by 0. PROVE (I.) in human urine in a state of 

 incipient decomposition. When kept in the dark this microbe develops into 

 colourless cultures, but if exposed to diffuse daylight or the sun's rays it elabo- 

 rates a sulphur-yellow colouring matter. This may, therefore, be regarded as 

 a probable means of protection. 



Many species of bacteria producing orange-yellow or orange-red colouring 

 matters are met with in air, water, and soil. Since they are of no particular 

 importance, it will be sufficient to merely mention a couple of them, viz., the 

 Micrococcus aurantiacus ( = Bacteridium aurantiacum), described by Cohn and 

 Schroeter, and the Bacillus aurantiacus, discovered by Frankland. 



The group of globular Schizomycetes to which the generic name of Sarcina 

 has been applied is rich in species producing red or yellow colouring matters. 



A few examples of the former having been already 

 given in previous paragraphs, it will now be sufficient 

 to consider merely those developing into yellow colonies. 

 The first observation of any sarcina species whatsoever 

 was made in connection with a species of this group. 

 JOHN GOODSIR (I.) in 1842 discovered, in the vomit 

 of a patient suffering from a diseased stomach, 

 colonies of microbes resembling bales of merchandise 

 in form, to which he applied the name Sarcina ventri- 

 culi (Fig. 33). His opinion that the microbe was a 

 vegetable organism led to a controversy only termi- 

 nated in 1847 by VIRCHOW (I.), who agreed with his 

 English colleague. Sarcina ventrwuli produces, how- 

 ever, but a faint yellow colouring matter. The cells 

 of the Sarcina flava, described by De Bary, which 

 measure 1-2 p in diameter, produce a yellow colouring matter, and this species 

 is distinguished from the Sarcina lutea, discovered by Schroeter, by its power of 

 liquefying gelatin. Paul Lindner prepared pure cultures of Sarcina aurantiaca 

 from Berlin u Weissbier " (white beer), the colouring matter of which organism 

 is, according to the researches of H. VON SCHROTTER (I.), allied to lipoxanthine. 

 No sarcina producing blue, violet, or green colouring matters are as yet known. 



00 

 I 



o 



I 



FIG. 33. Sarcina ventriculi. 



From the contents of a dis- 

 eased stomach, a-d. various 

 stages of development. 



