THE PHARMACOLOGICAL ACTION OF TUTU. 



295 



Experiment V. — 0-066 mg. Tutin per grm. Frog (R. temporaria — fresh caught). Weight, 15 grm. 



Time. 



11.43 

 11.55 

 11.56 

 11.57 

 12.0 



12.5 



12.10 



12.11 



12.12 



12.13 



12.15 

 12.16 

 12.18 



12.20 

 12.25 

 12.35 

 12.40 



1.0 



2.0 

 3.0 



Observations. 



1 c.c. 1 in 1000 tutin solution injected into dorsal lymph-sac. 



Sunk on to venter ; creeping about. 



Assumed bizarre position, hind legs being stretched out at right angles to body. 



Very transient opisthotonos. 



Blowing on the animal produced transient opisthotonos. Afterwards the frog tried to walk, 

 but was unable to raise itself from the ground, hence it merely slid along on its venter. 

 Hind-leg movements very stiff. 



Still sliding along ground for short distances. 



Made a few short jumps (clonic convulsion) ending in a slight opisthotonic attack. 



Another similar attack. 



Severe clonic convulsion (back arched) with cries. Belly appears blown out. 



Repeated clonic convulsions without cries. The frog remained on its back after the attacks 

 ceased. 



Slight movements — mainly attempts to turn over — -with mild cries. 



Placed on venter. At once assumed a peculiar position closely resembling emprosthotonos. 



Made few attempts to spring, croaking each time. Whole body presents a blown-out 

 appearance. 



Moving about, but movements incoordinate. Croaking. Eyes opened; corneal reflex sluggish. 



Placed on back. Remained motionless at first, then made unsuccessful attempts to turn over. 



Has not succeeded in turning over. Placed on venter. 



Moving about a little, with nose on ground. Movements incoordinate and apparently ex- 

 hausting. Lymph-sacs blown out. 



Has been quiet since last note ; now made repeated futile attempts to move. Presents a less 

 blown-out appearance. Placed on back. 



Quiet. Has made a few attempts to turn over. Placed on venter. 



No distinct improvement. Has moved inco-ordinately at times. Pithed. All stiffness im- 

 mediately disappeared. Heart beating well. 



Trout and Tadpoles. — Trout, a few weeks old, when put into 1 in 1000 tutin solution, 

 showed tremors of the tail in eleven minutes, marked twitches in thirty minutes, and 

 tetanic convulsions in less than an hour. Tadpoles were affected similarly. 



Action on Medullary Centres. 



The protocols given on page 293 show that in rabbits tutin diminishes the rate 

 of the heart-beat and increases the frequency of the ^respiration, and that the two effects 

 are in each case nearly reciprocally proportional. This relative effect is seen better 

 when the experiments are plotted as graphs (figs. 1 and 2). Fig. 1 shows the action of 

 a minimal effective dose of tutin, and demonstrates the slightly irregular reciprocity in 

 the effect on the pulse and respiration which is invariably seen after such small doses. 

 After moderate doses of tutin the curves of frequency of respiration and pulse become more 

 uniformly reciprocal — in the graph shown (fig. 2, Experiment II.) each curve is almost 

 a mirror curve of the other. This greater uniformity in the case of moderate doses is 

 probably due to the greater stimulus assuming more effective control of the medullary 

 centres, thus rendering them less liable to accidental variation from without. That this 

 influence on the heart-beat and respiration is due to an action on the medullary centres 



TRANS. ROY. SOC. EDIN., VOL. XLVII. PART II. (NO. 13). 45 



