14 U. S. BUREAU OF FISHERIES. 
THE PADDLEFISH. 
The study of the natural history and artificial propagation of the 
paddlefish in Bayou Pierre at Westdale, La., was continued by 
Dr. A. D. Howard, scientific assistant, with the cooperation of the 
Louisiana Conservation Commission. During March good catches 
of egg-bearing females and sufficiently ripe “males were obtained, 
but no females were ripe enough to allow of fertilization of eggs. 
Late in the month heavy rains flooded the Red River and Bayou 
Pierre and prevented the capture of fish in sufficient numbers to 
continue the investigation. . 
There are few added data regarding the breeding grounds of the 
fish and the time and manner ‘of spawning. Some information of 
minor importance was obtained regarding certain habits of the 
species. Bottoms suspected of being the breeding grounds of the 
paddlefish were dredged for the purpose of obtaining eges, but 
without success. 
POISONOUS ACTION OF GAR ROE, 
In a previous year experimental attempts to produce caviar of gar 
roe were made by Prof. C. W. Greene, temporary investigator. Out 
of this work it developed that the pigment in the gar roe is not a 
melanin as in the sturgeon roe, but a form of pigment that changes 
color under various chemical treatments of the roe. The pigment 
color is changed to an orange red on boiling the gar eggs, on treat- 
ment with alcohol or ether, and on salting. This changes the com- 
mercial quality of the product and gives easy methods for detecting 
the adulteration of sturgeon roe by gar roe. 
The important observation, however, was the demonstration of an 
active physiological principle of a toxic nature present in gar roe. 
It is apparently this principle that gives the unpleasant acrid taste 
to gar-roe caviar. When tested biolog gically by the method of feeding 
the natural product the following points were made: (1) Gar roe is 
poisonous to the chicken and to the rat; (2) it paralyzes the neuro- 
muscular mechanism of the chicken crop; (3) it produces in the rat 
an intestinal irritation with active diarrhea. 
During the summer of 1920 a series of experiments were made to 
chemically separate and biologically test the unknown toxic sub- 
stance. It was shown that (1) extracts in boiling water free from 
coagulable protein and (2) similar alcoholic extracts contained an 
active principle toxic to the heart of the frog; (3) globulin fractions 
niade by the method of salting out, centrifuging, and purifying by 
dialysis were sharply toxic to the heart: (4) the elobulin fractions fed 
to a young rat produced extreme diarrhea and death in about 20 
hours, effects comparable to feeding the entire fresh ovary; (5) the 
effect on the chicken’s crop was positively toxic; (6) not only was the 
crop paralyzed but an acute diarrhea occurred in the chicken through 
some alimentary canal poisoning; (7) these effects also occurred after 
feeding the purified globulin. 
Attempts to isolate and identify the individual chemicals, of which 
at least two classes are present, have thus far not been brought to a 
successful issue. Further experiments are planned. 
