FiTCHETT. — Phi/siological Action of Tut in. 315 



for a week on a solution of cane sugar in 0-1-per-cent. solution tutin (Exp. 

 115) ; but a 0-5-per-cent. solution quickly produced symptoms, and caused 

 death in half an hour or so (Exp. 116). 



The symptoms were very like those that characterize the action of the 

 poison in higher animals — namely, an initial lethargy, followed by isolated 

 tonic spasms of the wings and legs, exactly resembling the appearance met 

 with in pigeons in the early stages of poisoning, when one or other wing 

 is extended in rigid spasm for a moment ; then marked clonic spasm of the 

 wings recurring at intervals, and finally general convulsions, in which the 

 insect tossed and buzzed about until exhausted. In the latest stages the 

 flies lay on their backs, showing only occasional movements of the legs. 

 After death, distention of the abdomen was an invariable finding, and in 

 the case of a blowfly the exudation of a considerable drop of clear fluid 

 from the proboscis occurred. 



7. Action ox Larv^. 



(Exp. 117.) The eft'ect of the poison on maggots was tested by placing 

 some mince that had become infected by blowflies in solutions of tutin 

 of different strength for one hour, and then draining off the fluid. The 

 experiment was controlled by a portion of the mince being placed in normal 

 saline for the same period. On the day following, the maggots in the control 

 had hatched out, and were very active ; but in the mince subjected to the 

 action of a 0-5-per-cent. solution tutin no movement was seen, and only 

 one or two larvae were found moving in the mince that had been soaked 

 in tutin solutions of lesser strength. 



Experiments that were made on full-grown maggots showed that con- 

 finement for forty-eight hours in tutin solutions of strengths graded up to 

 0-05 per cent, had apparently no influence. As immersion in a 0-05-per-cent. 

 solution is about equivalent to a dose of 500 mlgm. per kilo, or 0-5 gram, 

 tutin is seen to be very inactive. 



8. Action on Molluscs. 



(Exp. 11-1.) Two cockles of about the same size were placed one in 

 sea-water and the other in a 0-5-per-cent. solution of tutin in sea-water, 

 freshly prepared. Equal volumes of fluid were aUowed. The cockle that 

 had been placed in the tutin solution, in five minutes opened its shell and 

 extruded its body. If touched it immediately withdrew, but came out 

 again at once. It kept opening and closing its shell, but did not withdraw 

 its body as the valves came together. It continued Uke this for twenty- 

 four hours, responding more sluggishly to a touch as time went on, and then 

 died. The control meanwhile had displayed no symptoms, but behaved 

 in exactly the way the other had done when it, in turn, was placed in the 

 tutin solution, and it also died. 



9. Action on Infusoria and Au(ebm. 



The action on infusoria and amoebae was examined in the following 

 way : — 



A drop of hay-infusion, containing infusoria, amoebae, monads, and 

 bacteria, was placed on a slide ; a drop of 0-1-per-cent. solution tutin was 

 added, and the specimen observed for an hour. A drop of the infusion to 

 which nothing had been added was used as a control. Another drop to 

 which a drop of normal saUne had been added was used to test the influence 



