462 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Dr. Dendy does not tliink it advisable, in the present state of our 
knowledge, to introduce the family Pharetrones into the system of recent 
Calcarea, but to regard Lelapia simply as a very specialize! form of the 
Grantiidse. 
Protozoa. 
Role of Acid in Protozoan Digestion.* — Misses M. Greenwood and 
E. R. Saunders have made a careful investigation into the question of 
the intracellular formation of acid in Protozoa ; their aim was to deter- 
mine the relation of acid to the solution of nutritive matter in these 
simple organisms, rather than its actual formation ; widely different 
types were made use of— the Infusorian Carchesium polypinum and the 
plasmodia of certain Mycetozoa. In the habits of the latter they found 
a striking likeness to the physiological actions of Amoeba ; the fashion 
of ingestion, the exclusive digestion of proteid matter, the localiza- 
tion of solvent processes in marked vacuoles served to recall vividly 
the corresponding phenomena in Rhizopods. They consider, there- 
fore, that they are entitled to draw generalizations from these unlike 
forms. 
The ingestion of solid matter, whatever its nature, stimulates the 
surrounding cell-substance to secrete acid fluid, the presence of which 
may be demonstrated by colour change in litmus, in Congo red, and in 
alizarin sulphate, and by the solution of calcium and magnesium phos- 
phate. The outpouring of acid is not accompanied by any digestive 
change on nutritive matter; ingesta may indeed be stored for many 
hours before they are dissolved, but the formation of the digestive 
vacuole, whether immediate or delayed, is preceded by the development 
of the acid reaction, and followed by its diminution. Later on, the 
vacuoles and ingesta reddened by litmus become violet, and the end of 
normal digestion finds them pale blue, so that acid and acid combina- 
tions are alike absent. The acid is certainly free at one time, and is 
not carbonic, though it is, probably, an inorganic acid. 
The authors contract the relation of the secretion of acid to proteo- 
lytic activity in Protozoa with the fundamental structural changes 
which accompany digestion in Vertebrates, and point out that although 
the secretion of acid is excited by all ingesta, the true digestive vacuole 
is only formed under the stimulus supplied by nutritive matter. 
Protozoa of Helsingfors.^ — Dr. K. M. Levander publishes a pre- 
liminary list of Protozoa found in fresh, salt, and brackish water around 
Helsingfors. It includes 16 Rhizopoda, 27 Flagellata, and 72 Ciliata, 
of which six are new. 
Protozoa in Herpes Zoster. f — M. Wassiliewski, who has examined 
274 cases of zona, has found among the normal epithelial cells larger 
cells containing a foreign body. These large cells contained 6-8 
diaphanous corpuscles usually enclosed in a cyst. Similar bodies were 
found in epithelial cells when only slightly enlarged. They lay near 
* Journal of Physiology, xvi. (1894) pp. 441-67 (1 pi.). 
t Zool. Anzeig., xvii. (1894) pp. 209-12. 
+ Correspondenz-Blatter des Allg. Aertzl. Vereins f. Tkiiringen, Anuee 24. See 
Ann. de Microgruphie, vi. (1894) pp. 178-9. 
