1887 .] Dr A. B. Griffiths on Organs of the Invertehrata. 235 
cyanates. The inorganic constituent, as far as I could make out, 
consists only of calcium phosphate. 
Turning once more to the soluble zymase (ferment) contained in 
the secretion, it can he isolated by precipitating the secretion with 
dilute phosphoric acid, adding lime-water, and filtering. The pre- 
cipitate was dissolved in distilled water, and then reprecipitated by 
alcohol. This precipitate converts starch into glucose sugar. 
Fig. 3 . — a and b, Salivary gland of Periplaneta orientalis (much enlarged). 
I have already mentioned that the secretion of the salivary 
glands of Periplaneta are alkaline. Out of 80 animals, I found 4 
with the secretion decidedly acid. This acid property is most 
probably due to pathological changes in the secretion of the said 
four animals. 
The largest quantity of diastatic or “ soluble ” ferment was to he 
found in the secretion obtained from the glandular portion of the 
organ and not from the salivary receptacles (fig. 3, a). 
The salivary glands of Helix aspersa (snail) yielded a soluble 
ferment, capable of converting starch into glucose sugar. The 
ferric-chloride test failed to show the presence of sulpho-cyanates. 
The mineral ingredients found were calcium and chlorine ; but I 
