388 SUMMARY OF CURRENT RESEARCHES RELATING TO 



and bibliography of recent progress. Attention is called to investiga- 

 tions like the following : — Dobell's stndy of amoeba and coccidia in 

 man, La Eue's monograph on Proteocephalidfe, Leiper's study of 

 Bilharzia, Nakagawa's unravelling of the life-cycle of Paragonimus 

 ivestermaiii, Magath's monograpli on Gamallanus anicricanm ("the 

 most significant work on a single nematode species since the researches 

 of Looss on Ancylostoma duodenaU "), and the work of the Rockefeller 

 Commission in connexion with hookworm. J. A. T. 



Variations and Modifications. — Arnold Pictet (Oompfes Rendus 

 Soc. Pliys. Hist. Nat. Geneve, 1921, 38, 64-7). Greographical races of 

 Lepidoptera with hereditary characters must be and can be distinguished 

 from false races, with acquired modifications (or " somations ") similar 

 to the local peculiarities of the true geographical races, but not lasting. 

 On mountain plateaux there are found forms with the hereditary peculiarity 

 A B, due to a crossing of A and B forms which belong to different 

 sides of the mountain, but meet at the top. But there are likewise 

 absolutely similar A B forms, which are A's and B's that have migrated 

 to the plateaux and have been individually modified there. But the 

 A B peculiarity of these migrants is not hereditary. Experimental 

 results will be discrepant if two kinds of A B (variational and modifica- 

 tional) are confused. Pictet's experiments are quite against the 

 hypothesis of the transmission of somatic modifications. J. A. T. 



Increase in Quantity of Anti-bodies. — A. Sordelli (Comptes 

 Rendus Soc. Biol., l'J20, 83, 1526). The presence of anti-bodies may 

 be due to placental transmission from the mother, or to the milk, or 

 they may be formed as a reaction to an intruding microbe, or they may 

 arise spontaneously. The author's point is that the quantity of an 

 anti-body increases as the animal grows older. This is seen in the 

 diphtheritic anti-toxin in man and in horse, in the cholera agglutinin 

 in the guinea-pig, and in the dysenteric agglutinin in the horse. The 

 author concludes in favour of the spontaneous production of anti- 

 bodies. J. A. T. 



Secondary Sex-characters in Elasmobranchs. — W. Harold Leigh- 

 Sharpe {Journ. Morphol., 1!)21, 35, 359-80, 15 figs.). K study of the 

 structure and functions of the claspers, clasper siphons, and clasper 

 glands in various Elasmobranchs — Galeas vulgaris, Mustelus vidgaris, 

 Lamna cornuhica, and Rltina squatina. The functions of the clasper 

 gland, in the Lamna type at least, are comparable to those of the 

 prostate — e.g. (1) lubrication and provision of a vehicle for the sperma- 

 tozoa ; (2) control of erection ; (3) activation of the spermatozoa ; and 

 (4) providing nourishment for the spermatozoa. The clasper glands 

 are developed, however, as invaginations of the epidermis. On the 

 outer borders of the upper lip of Rhina squatina there is a patch of 

 cells of the same type and structure as the clasper gland ; it is evidently 

 a mucus-secreting gland and not an organ of special sense. The rectal 

 gland of Scyllium has a kidney-like structure, except that there are no 

 Malpighian bodies and the blood-supply is slight. It may be an 

 excretory organ, getting rid of poisonous substances not eliminated by 

 the kidneys. J. A. T. 



