486 Prof. J. B. Haycraft. On the Action of a [Apr. 3, 



action of the leech extract on the coagulation of milk by rennet and 

 on myosin. Rennet mixed with a watery solution of leech has no 

 less power of clotting milk than another portion mixed with water 

 alone. The leech extract does not hinder in any way the clotting of 

 myosin. The latter was prepared from frog's muscle in a somewhat 

 shorter and, I think, a better way than that described by Kiihne. 

 Two mortars containing poanded glass were placed in a freezing 

 mixture. One held a few drops of normal salt solution, and the 

 other a like quantity of normal salt solution of leech extract. The 

 legs of a frog were washed out with normal salt solution, the muscles 

 cut out, dried on blotting-paper, placed in the mortar, and ground 

 with the glass into a frozen pulp. This was then tied up in a piece 

 of calico, and the myosin expressed and filtered. Its preparation 

 is most easy, and can be done without fail in the hottest weather. 

 The myosin obtained from the muscle to which the leech extract had 

 been added coagulated in 10 — 15 minutes, and the other in from 

 20 — 25 minutes. The experiment was repeated with like results. It 

 may be remarked that if the clotting of myosin is due to a ferment, 

 this has not yet been isolated. 



Inasmuch as during contraction chemical changes occur very 

 similar to those seen in rigor mortis, and inasmuch as in the latter 

 the coagulation of myosin is a prominent fact, some have held that a 

 contraction of a muscle is due also to a partial clotting of the myosin. 

 This view I have never held to be anything but fanciful, for reasons 

 which cannot be stated here. Dr. Lauder Brunton, however, sug- 

 gested to me, that by soaking rog's muscle in the leech extract, and 

 studying its contractility, some light might be thrown on the subject. 

 I accordingly cut out from the limbs of a pithed frog some of the 

 principal muscles, i.e., the sartorii, carefully removing them with as 

 Little injury as possible. Those of one side were placed in normal 

 salt solution, and those of the other in normal salt solution of leech. 

 Comparisons were of course only made between the corresponding 

 muscles of both sides. From time to time the irritability was tested 

 by currents from an induction coil. In all cases the muscles placed 

 in leech extract lost their irritability some time before the corre- 

 sponding ones placed in salt solution. In one experiment with two 

 sartorii, the left placed in leech extract died in 35 minutes, the right 

 in 70 minutes. Two pectoral muscles attached to the bone lived much 

 longer — one longer than I had conceived was possible — that in leech 

 extract for 12 hours, and the other for 51 hours. 



In these experiments those placed in leech extract almost from the 

 first contracted more feebly when stimulated. On more than one 

 occasion I obtained partial recovery when a muscle was removed from 

 the leech extract and placed in fresh salt solution. The only con- 

 clusion one can draw is, that the leech extract somewhat hastens the 



