HOFFMANN'S EXPERIMENT 413 



fat-staining reagents, and are split into their components by 

 the ferment action of autolyzing tissue (but not by trypsin). 



Having in some degree come to an appreciation of these 

 points, a further step may be taken and attention given to 

 other examples of the supposed formation of fat from 

 protein. 



Formation of Higher Fatty Acids by Microorganisms. 

 We at once encounter here the fact, of importance to appre- 

 ciation of the general problem, that we must acknowledge 

 without question the power of forming fat from protein as 

 belonging to the lower vegetable organisms (a power which, 

 as far as the animal organism is concerned, if not absolutely 

 contested, can be recognized only conditionally and with 

 much reservation with the preformation of sugar from pro- 

 tein in mind). A long time ago Emmerling concluded that 

 higher fatty acids are produced in culture of staphylococcus 

 pyo genes aureus on egg albumin. The experiments of several 

 American authors (Beebe and Buxton) 41 seem particularly 

 significant in this connection. They have shown that if 

 bacillus pyocyaneus be cultivated on media free from sugar 

 and from fat, such quantities of fatty substances are formed 

 that they become evident on the culture surface in the form 

 of microscopic needle-shaped crystals. 



Hoffmann's Experiment with Fly-maggots. The ability 

 of microorganisms to construct fat out of protein explains 

 other points; particularly the famous maggot experiment 

 made by Franz Hoffmann in the early seventies. This in- 

 vestigator determined the fat-content of a portion of a num- 

 ber of fly-eggs and then allowed the remainder to develop 

 upon defibrinated blood. It was proved at the close of the 

 experiment that the fat-content of the larvae exceeded by 

 tenfold the sum of the egg-fat and of the fat in the blood. 

 Long ago Pfliiger's acumen suggested the apparently perti- 

 nent interpretation for this experiment, which was later 



41 S. P. Beebe and B. H. Buxton (Cornell Univ., New York), Amer. Jour, of 

 Physiol., 12, 466, 1905. 



