296 
Journal of Agricultural Research 
Vol. XXXI, No. 3 
diseased leaflets. With diseased leaves, the protein nitrogen was 
greater than that present in the corresponding healthy control leaflets, 
in the case of both fungi. The percentages of humin nitrogen was 
noticeably greater in the diseased leaves. 
This outline of the relative nitrogen constituents for healthy and 
diseased celery shows that with these two parasitic diseases the re¬ 
sults of analyses follow closely those of spinach mosaic and those of 
the unknown cabbage disease to which reference has been made. 
Table V. —Deviation of diseased material from healthy material—Comparison of 
. celery diseases with results obtained by Jodidi et al. with spinach and cabbage 
[Hot water extract of spinach and cabbage was used for the acid amide, “humin,” diamino, and mono- 
amino tests. The results are expressed in percentage of total nitrogen] 
Celery 
Spinach 
mosaic 
Cabbage 
unknown 
disease 1 
Cercospora 
apii 
Septoria 
apii 
Nitric nitrogen_ _ 
-3.4 (-2.7) 
+1.3 
(+) 
-2.6 
-0.2 
+4.1 
-1.3 
-3.1 
+6.1 
, 61 
-0.1 
+1.0 
(+) 
-3.9 
4 -1.7 
+1.3 
-3.6 
2-1.22 
3+0.63 
2 (+) 
-6.42 
Ammonia nitrogen_ 
Nitrite_ 
(+) 
Total hydrolyzable nitrogen____ 
Acid amide________ 
• * -2.89 
2+0.94 
2 -2.33 
4 -7.19 
+0.81 
-4.04 
“Humin”____ 
Diamino_I_ 
Mono amino __ 
Protein nitrogen_ 
+4.8 
83 
3+9.29 
2 77 
+21. 72 
77 
Relation of total nitrogen of diseased to healthy material-.. 
1 Figures computed from Tables II, III, and IV (leaves), Jodidi {If). 
2 Figures computed from sample A, Table V, p. 1891, Jodidi {12). 
3 Figures computed from Tables III and IV, Jodidi et al. {IS).. 
4 Plus ammonia nitrogen. 
It will be noted that in every case the deviation of diseased 
material from healthy is of the same character. Jodidi, because of 
the similarity of the chemical picture of diseased cabbage and 
spinach, deduced that the cabbage disease was of mosaic nature. 
The results of the analyses here presented show that such a deduction 
is unwarranted. 
The results here obtained seem best interpreted from the point 
*of view of metabolism of fungi. A parasitic fungus maintains itself 
by establishing a food and water relation with a host. From the 
nitrogenous material of the host it builds its own kinds of proteins. 
Since Nageli’s classic researches {18), it has commonly been accepted 
that the splitting off of ammonia is the course of protein decomposition 
by microorganisms. The presence of ammonia in cultures of fungi 
on richly nitrogenous media has often been demonstrated. Wehmer 
{26) in cultures of Aspergillus niger on peptone solution obtained 
marked formation of ammonia. Further evidence of the formation 
of ammonia from proteins have been given by many others with a 
wide range of organisms (4, p- 310), But there are intermediate 
steps in the process and these , are poorly known. The work of 
Butkewitsch {6) maybe cited as throwing some light on this process. 
Apergillus niger , Penicillium glaucum , Mucor racemosus , and Rhizopus 
nigricans were shown by him to split off not only ammonia from pep¬ 
tone and fibrin, but also aminoacids, leucin, and tyrosin. (See also 
Klotz, 14.) These products were in turn decomposed. From the 
work of various investigators it has been shown that the process is 
