118 GENETICS [Box. Absts., Vol. IX, 



side agencies, there is an automatic self-pollination of flowers in the rose at an early hour in 

 the morning. While cross-pollination can occur, there is a surprising amount of selfing, much 

 of it being accomplished by thrips. A number of cleistogamous flowers were found in R. 

 omissa. Experiments have shown that practically all of the local rose microgenes depend upon 

 self- or cross-pollination for the setting of seed and in the event of failure of these are, to some 

 extent, facultatively apomictical. Dingler has already demonstrated apomixis in a form 

 of R. ruhiginosa, and Lundstrom in R. glauca and R. coriifolia. The writer holds that such 

 apogamy as is found in the rose has its origin in hybridity. Some polyembryony is reported 

 and various natural hybrids of roses are described. [See also Bot. Absts. 9, Entry 73S.] — A. 

 C. Eraser. 



746. Herwerden, M. A. van. [Dutch rev. of: Seiler, J. Geschlechtschromosomen- 

 Untersuchungen an Psychiden. I. Experimentelle Beeinflussung der geschlechtsbestimmen- 

 den Reifeteilung bei Talaeporia tubulosa Retz. (Sex chromosome investigations on psychids. 

 I. Experimental influencing of sex-determining maturation division in Talaeporia tubulosa 

 Retz.) Arch. Zellforsch. 15: 249-268. 1 pi. 1920 (see Bot. Absts. 7, Entry 1S36).] Genetica 

 3:79-81. 1921. 



747. HopPLi. [German rev. of : Christeller, E. Untersuchungen an kiinstlich hervor- 

 gebrachten Hermaphroditen bei Schmetterlingen. (Investigations on artificially produced 

 hermaphrodites among Lepidoptera.) Schrift. Phys. Okonom. Ges. Konigsberg 59: 1918.] 

 Centralbl. Allg. Path. 30: 512-514. 1920. 



748. King, Helen Dean. A comparative study of the birth mortality in the albino rat 

 and in man. Anat. Rec. 20: 321-354. 1921. — The normal percentage of still births in rats 

 for 31,670 births is 1.31. After correction, 2per cent seems the high limit. For man numerous 

 data ranging from 3.04 per cent to 5.67 per cent are given. The indications are that in higher 

 mammals from 2 to 4 per cent of full-term fetuses are dead. The sex ratio of normal living 

 rats is apparently 104.1 males to 100 females; this, however, is subject to corrections which 

 makes 107 a more nearly correct estimate. In 415 still births (same material) the sex ratio 

 was 129.3. The human sex ratio of living births shows a norm of about 105.5. The sex ratio 

 of 13,635,986 still births (Nichols) is 131.6. The author estimates the primary sex ratio and 

 criticizes Morgan's hypothesis to explain the constant sex ratio in man. He also considers 

 the evidence that the season influences the percentage of still births but concludes that such 

 influence is negligible. In rat and man early postnatal mortality is about the same and is 

 "somewhat higher" than the birth mortality. Causes and extent of birth mortality are 

 given as follows: (a) Malposition of fetus and disease, about 1 per cent of human fetuses 

 (Mall) but very rare in rats, — 4 in 50,000. (b) Size of fetus, "important" in humans but 

 not operative in rats, (c) Physical condition of mother, probably important in rats, (d) 

 Age of mother: Very old rats and both very young and very old human mothers appear to 

 give higher percentage of still births than those at zenith of reproductive period, (e) Con- 

 genital debility, over 50 per cent in humans and "practically all" cases in rats. The author 

 discusses the control of percentage of still births and believes fetal nutrition to be an important 

 factor; age of mothers is probably operative as a factor through this same medium of nutri- 

 tion. Since the earlier the embryonic age, the greater the excess of male abortions that occur, 

 "inadequate nutrition cannot be considered as the primary cause of the greater mortality 

 among male fetuses in general." Lillie's hj'pothesis of influence of sex hormones of mother 

 on mortality of male fetuses is discussed. Inherent dissimilarity of sexes as regards consti- 

 tutional vigor may have a basis in the amount of chromatin possessed by the ovum. The 

 assumption is made that, from conception, the embryo that is to be a male has a constitution 

 "inherently v/eaker" than the embryo that is to become a female; on this basis experimental 

 facts may be explained. — C. C. Little. 



749. Koltonski, Hermann. Uber Erblichkeit der Ovarial-, besonders der Dermoid- 

 cysten. [On the inheritance of ovarial cysts, especially the dermoid cysts.] Zeitschr. Krebs- 

 forsch. 17: 408-416. 1920. — Five patients belonging to 2 families are considered. I. (a) 



