FiTCHETT. — Physiuloyical Action of Tut in. 317 



proceeded vigorously in the presence of even 04 per cent, tutin. Some 

 slight differences in the rate of fermentation that were noted were probably 

 due to differences in the amount of yeast added. (For details of experi- 

 ments, see protocols, Exps. 122, 123, 124.) 



12. Germination of Seeds. 



The action of tutin on the germination of seeds was tested by soaking 

 mustard-seeds in solutions (in normal saline) of various strengths (0-1, 0-2, 

 0-3, 04, and 0-5 per cent.) for twenty-four hours (Exp. 125). The seeds 

 were then sown on pieces of felt in separate tin boxes, appropriately labelled, 

 and kept moist with water. An equal number of seeds was sown on each 

 piece of felt, and the experiment was controlled by seeds that had been 

 soaked for the same length of time in normal sahne. The day following, 

 all the seeds had germinated, and they were therefore replaced in their 

 respective tutin solutions for a further period of twenty-four hours, and 

 then sown again. During the next week the progress made by the seedlings 

 was observed, and the effect of the tutin on their development noted. 



It was found that the seeds progressed more or less in order of the weak- 

 ness of the solutions in which they had been soaked : thus, the growth of 

 those that had been soaked in normal saline, in 04 per cent., and in 0-2 per 

 cent, tutin was the most vigorous, while those that had been soaked in 

 0-3, 04, and 0-5 per cent, made slow progress, and all the seedlings in these 

 lots did not continue to grow. In a fortnight, however, little difference 

 was to be noted in any of the seedlings that had developed at all, one or 

 two of the 0-5-per-cent. seedhngs that were growing being as well developed 

 as those that had been soaked in saline. 



This result may possibly be due to the effect previously noted on bacteria, 

 certain forms of bacteria being necessary to the growth of plants. From 

 experiments on invertebrates, bacteria, &c., it may be inferred that tutin 

 is toxic to any given form of life in proportion to its complexity of organiza- 

 tion. Wherever a nervous system is sufficiently developed, the toxic action 

 is greatest; but that it has some injurious influence on primitive protoplasm 

 may also be seen from its effects on paramoecia, bacteria, &c. 



13. Action of Tutin on Tissues. 

 From the symptoms observed when studying the general action of the 

 poison on mammals, it seemed very evident that the nervous system was 

 the part chiefly affected. Nervous tissue will be considered later, and the 

 action of tutin on otlier tissues will be recorded first. 



(a.) Action on Primitive Protoplasm. 

 As is shown in Exp. 118, tutin, as compared with quinine, is not a strong 

 protoplasmic poison. That it has some deleterious action on living proto- 

 plasm is shown by the experiments on putrefactive bacteria, on the germina- 

 tion of seeds, and on paramoecia (Exps. 121, 125, 119), though it is doubtful 

 if the action here is more than might be exerted by any foreign substance. 



(b.) Ciliated Epithelium. 

 The action on ciUa was tested in the following way : A few bars from 

 the gill of a cockle were placed on a slide in a drop of sea-water, and ex- 

 amined with a power of 80 diameters. In the first experiment, the prepara- 

 tion was covered with a cover-glass, but in the later experiments cover- 



