I9I3] Alfred P. Lothrop 543 



tity of toxin as do the aerial filaments, Furthermore, the toxin is 

 present in both sexes of the fungus in large amount. We have not 

 determined whether one sex contains a greater absolute quantity 

 than the other. 



The toxicity o£ the Rhisopus extract may be better understood 

 by saying that a Solution containing the water-soluble substances 

 extracted from 0.045 S^- o^ ^^^ ^O^ fungus, when injected intra- 

 venously, is sufficient to kill a 1.35 kilo rabbit in less than two 

 minutes. Convulsions begin almost before the needle can be with- 

 drawn, and are followed by great turgidity of the ehest and abdomen, 

 then by relaxation of the rigid abdomen, throwing the head back- 

 ward with cough-like movements of the diaphragm, protrusion of 

 the eyes, and death. When a dose containing the toxin from a 

 greater quantity than 0.045 g^i- is injected, the animal is often 

 dead before the needle can be withdrawn, with no convulsive move- 

 ments and only a sudden turning of the head and the sinking of 

 the body on one side. A sub-lethal dose causes extreme lethargy, 

 lasting for 48 hr. or more, during which time the animal moves 

 only when forced to do so. This may be followed by complete 

 recovery. We have not as yet elucidated the chemical nature of the 

 toxin. Its activity is not diminished by peptic digestion for three 

 hours, nor is it affected when its aqueous Solution is heated to boil- 

 ing for 10 min. Apparently, therefore, it is not a toxalbumin. 



One of US (B) has shown that Rhizopus is nearly universally 

 distributed and is almost certain to appear as an infection on starchy 

 food under suitable moisture conditions, its occurrence being so 

 common as to have earned for it the name, " Bread-mould." While 

 connected with the Agricultural Experiment Station of the Univer- 

 sity of Nebraska, one of us (G) coöperated in an Investigation of 

 the origin of the "corn-stalk disease," which causes the death of 

 thousands of cattle in the Middle West each year, and which is, 

 in some way, connected with the use of corn stalks as fodder. At 

 that time no known toxin could be detected in the stomachs of the 

 diseased animals, and the direct cause of the disease has never been 

 elucidated. 



The method of growth of the fungus, its wide distribution, as 

 well as certain of the Symptoms produced by the toxin which it 



