766 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the apparently broken points becoming converted into an extremely thin 

 hyaline layer, which sends out pseudopodia-like processes. As a result 

 of all its changes, the ectoderm of the larva of Spongilla becomes 

 completely converted into the epithelium of the young Sponge. 



Sections through young oviform larvas show that the so-called endo- 

 dermal nucleus is not an indifferent mass of tissues, but contains more 

 or less perfect flagellate chambers, as well as spicules and other meso- 

 dermal elements. The spindle-shaped cells wliich Goette describes as 

 lying immediately beneath the ectoderm were also fuund by Herr Maas 

 to be always separated from it by a layer of mesodermal cells. Sections 

 made after the larva has become fixed show this relation of parts very 

 distinctly. 



Protozoa. 



Biitschli's Protozoa.* — Prof. O. Butschli has brought to completion 

 the work on which he has been engaged for the last ten ye irs. In 

 the presence of this great undertaking, so successfully completed, we 

 may be allowed to depart a little from the reserve which characterizes 

 the abstracts in this journal and offer him, in the name of general 

 biological as well as specially microscopical students, our congratula- 

 tions and thanks for this monumental work. 



The pages which remain to be reported on treat of the Suctoria, 

 which are fully dealt with ; to these there are appended a shoft notice of 

 Haeckel's system of the Eadiolaria published in 1887, a very interesting 

 postscript relating to the history of the work, a systematic index of names 

 extending over sixty columns, an index of authors, a useful note as to 

 the pages at which some general questions are discussed, and a few 

 corrections and additions. 



Psychology of Protozoa.f — Dr. G. J. Eomanes reviews the two 

 works whose titles are cited below ; % of the first he declares that but 

 for the title-page he would have doubted the authorship of the work. 

 The second is " charged throughout with the experimental work of a 

 physiologist, and with the analytical powers of a well-instructed mind." 

 There does not seem to be any evidence at all of even the lowest degree 

 of mental life in any unicellular organisms. The Protozoa afford an 

 exception to the general rule that in excitable tissues the principal seat 

 of excitation is the kathode on closing and the anode on opening a 

 galvanic circuit. When a galvanic current is closed through a drop of 

 water containing a number of Protozoa, they will all begin to travel 

 rapidly aud directly to the negative pole, and, if the current be left 

 closed for a few seconds, will all become congregated thereat. On now 

 opening the current they will all begin to travel towards the positive 

 pole, but then soon segregate. By using a movable kathode of harmless 

 material the Protozoa may be led about like a flock of sheep f )llowing 

 their shepherd. No evidence, but rather the contrary, was collected as 

 to the value of the nucleus as a co-ordinating centre of movements, 

 ciliary or otherwise, for unnucleated portions continue to exhibit all the 

 same spontaneous movements as the nucleated. 



* Bronn's Klassen u. Ordnungen, i., Protozoa (1889) pp. 1841-2035 (pis. 

 Ixxvi.-ix.). t Nature, xl. (1889) pp. 541-2. 



X A. Binet, ' The Psychic Life of Micro-organisms.' Translated from the 

 French (Chica<i;o, 1889). Dr. Max Verworn, ' Psycho-physiologische Protisten- 

 Stiulien : expirimen telle Untersuchungen ' (Jena, 1889). 



