ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 307 



seen in pulmonary embolism are also in the main of splenic origin, but 

 may also come from the marrow. Besides free platelets and aggregated 

 platelets there are other elements in the spleen, approaching the platelet 

 type, and from these platelets may perhaps arise as well as from the 

 megakaryocytes. J. A. T. 



Eosinophilic Leucocytes in Thymus of Postnatal Pigs. — J. A. 

 Badertscher (Anaf. Record, 1920, 18, 23-34). Granular eosinophilic 

 leucocytes are formed in the thymus of the postnatal pig. It follows 

 that the bone-marrow is not the only source of the granular leucocytes 

 found in the blood. The fact bespeaks for the thymus a function with 

 which it has not been generally credited. It is indicated that the 

 lymphocytes (especially the large lympliocytes) in the thymus have, to 

 a limited extent at least, the potentiality of the premyelocytes 

 (myeloblast, h?emoblast, primitive blood-cell, " lymphocyte ") in the 

 bone-marrow in so far that they are capable of developing into some or 

 all (perhaps variable in different mammalian species) of the types of the 

 granular leucocytes found in the blood. J. A. T. 



Theory of Symbions in all Cells. — Auguste Lumiere (Le Mythe 

 des SymMotes, 1919, Paris, xi + 209, 50 figs.). Criticism of Portier's 

 heresy that all the elements of Protozoa and Metazoa, and indeed 

 practically all organisms except bacteria, contain symbiotic microbes by 

 aid of which synthetic metabolic process is made possible. It is 

 admitted that the normal tissues of vertebrates often contain quiescent 

 saprophytic micro-organisms, and these have supplied in part a basis 

 for Portier's extraordinary theory of symbions ; but the microbes in 

 question have not the qualities of Portier's " symbiotes." Mitochondria 

 have also been mistaken for microbes, while they are only formed 

 colloid aggregates in the cytoplasm. To suppose that vitamines are 

 carried by special symbions is quite gratuitous. J. A. T. 



Blood-coloured Muscle in Fish.— IVzuRU Okuda (Journ. Colleye 

 of Agric. Imp. Univ. Tokyo, 1919, 7, 1-28, 1 fig.). In Katsuuwnus 

 pekmiis and Auxis tapeinosoma the blood-coloured flesh in the lateral 

 muscle (common to many fishes) contains more ether extract and less 

 carbohydrates, soluble matter, creatine and nitrogenous matters. It is 

 superior to the ordinary flesh in respect of its contents of phosphorus in 

 lipoid form, but inferior in its content of phosphorus in inosinic acid 

 form. Each kind has about the same quantity of protein-sulphur and 

 volatile sulphur, but the red flesh has more taurine. It also has more 

 lecithin, haemoglobin, and hypoxanthin. Other differences are noted. 



J. A. T. 



Cells of Tadpole's Tail.— W. J. Schmidt (Zool. Anzeiger, 1920, 51, 

 49-63, 7 figs.). A description of (1) the ordinary pigmented epidermic 

 cells in the outer epithelial layer, (2) the bi-nucleate strongly pigmented 

 giant cells of the same layer, (3) the occasional ciliated cells, (4) the 

 pigmented wandering cells which are usually found in the epithelium 

 but sometimes in the cutis, and (5) the stellate melanophores^of the 



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