Malcolm. — Toxicity of Tutu Fruit and Seed. 3 



amounted to 50 to 60 per cent, of the whole dose of crushed seed. In 

 order to test whether such residues contained any appreciable amount 

 of tutin, a fairly large amount was dried, extracted with ether, and the 

 ether-soluble material administered to a rabbit in watery suspension by 

 stomach-tube. It produced no symptoms whatever in a dose equal to 

 7'5grm. of "husk" per kilogram body weight, so that the bulk of the 

 tutin may be supposed to have been present in the watery suspension. 

 When the seed was administered in this way the results shown in the 

 table were obtained. 



Toxicity op Seed. 



* This animal had been used for exp. 274, and had then had its thyroid gland removed, 

 about four weeks before being used for exp. 29.5. 



The percentages of tutin in these experiments have been calculated 

 from the results of previous work by Fitchett and other experiments 

 by the writer. The standards adopted for rabbits wei-e that a dose of 

 6 milligrams per kilogram produces no marked symptoms ; 6 milligrams 

 produces symptoms in one hour and a half, and is ultimately fatal ; 

 7'5 milligrams produces symptoms in about half an hour, and death 

 between one and two hours. 



Sample I of the seed was used in only one experiment, and in that 

 case was more toxic than sample II. It occurred to me that this might 

 be due to a difference in the toxicity of green seed as compared to ripe, 

 for, owing to the method of collecting it, sample II contained more ripe 

 seed than sample I. Fortunately, although it was late in the year 

 (May), I was able to procure locally sufficient green berries to put the 

 matter to a test. 



At first it seemed impossible without serious loss of time to mechanic- 

 ally separate the small unripe seeds from the green fleshy petals, and 

 after separating enough to find the percentage of seed present (18-2) 

 the whole unripe fruit was administered in the form of a watery 

 suspension. This gave the following results : 27 grm. fruit per kilogram 

 caused death in forty-five minutes; 14-4 grm. in ninety-five minutes; 

 10 grm. in two hours and a half. As 10 grm. fruit contained only 

 1-8 grm. seed, it followed that either the unripe seed contained a very 

 large amount of tutin, or that, at this stage, it was also present in 

 the fleshy petals. To decide this point it was necessary to obtain a 

 clean sample of unripe seed, and after several attempts the following 

 method was found to be successful : Berries were dried in air at a mode- 

 rate temperature and ru.bbed between the fingers ; by this means the 

 seeds were isolated from the remainder. The material was then put. 



