38 PHYSIOLOGY AND TOXICOLOGY 



dog, and man, a circumstance Avhicli necessarily impairs the interest and value of 

 this particular branch of our subject. 



Since the discovery by Leuchs, of the power of saliva to convert boiled starch 

 into grape sugar, observers have been undecided as to whether or not pure parotid 

 saliva possesses this power. The weight of authority at present is undoubtedly 

 against it, but in the absence of any positive decision, I have conceived it neces- 

 sary to learn whether or not the supposed venom saliva had this faculty. 



Exjjeriment. — In three test tubes of the same size, was placed an equal amount 

 of boiled starch-water, in which I had failed to detect the presence of grape sugar. 

 To the first of these were added three drops of pure venom. To the second were 

 added three or four drops of mixed saliva from my own mouth. The third was 

 left without any addition, and all were exposed to a temperature of 78° F. 



No. T. Venom and starch-water was examined at intervals, but gave no re- 

 action with the cupro-potassa test until forty-eight hours had elapsed, when sugar 

 was found to be present, but not in large amount. 



No. II. Starch-water and saliva contained sugar at the close of half an hour. 

 Within three hours the sugar was present in abundance. 



No. III. Starch-water alone exhibited no traces of sugar until forty-eight hours 

 had elapsed, when it was to be detected, although present in no large quantity. 



In a second series of experiments, results so nearly similar were obtained, that 

 it is needless to relate them here. 



Since it has been asserted by Wright, that acid saliva does not possess the same 

 converting power as the ordinary alkaline fluid, and as the venom saliva was con- 

 stantly acid, I repeated the experiments with the following modification. 



Exjjeriment. — In two test tubes was placed about half an ounce of thin starch- 

 water. To the first were added four drops of venom, which I had rather more than 

 neutralized with potassa. 



The second I left without this addition, and exposed them both to a temperature 

 of from 77° to 87° F. At the close of twenty-four hours, neither of them exhibited 

 any traces of sugar, but after twenty-eight hours, sugar was present in the venom 

 tube and not in the other. These experiments were also repeated on subsequent 

 occasions with like results. 



I conceive that we have a right to infer that the venom has no peculiar power 

 to convert boiled starch into grape sugar, and is, in this respect, almost absolutely 

 inactive. 



My next observations were directed towards ascertaining whether the venom 

 gland, like the ordinary salivary glands, would yield to water its active principles, 

 and so give rise to infusions, in each case, resembling the saliva of the respective 

 glands. Thus, since M. Bernard's researches, it is well known that an infusion of 

 the submaxillary or parotid glands has all the properties of the normal saliva of 

 these organs. According to this author, the solid matters of the various salivas 

 are constantly deposited in the glands, and are rapidly washed out of them by a 

 flow of thin solvent fluid from the bloodvessels, at such times as the secretion 

 may be needed. If, now, the solid matter of the venom be in like manner a con- 

 stant portion of the bulk of the gland, it was to be presumed that an infusion of 



