128 



SCIENCE. 



[Vol. XIX. No. 474 



the good ones ia hearing, those in the senses of pressure and 

 temperature, the accurate measurements of visual sjiace, tlie 

 measurements of the reaction-time, etc., have all tended to 

 place experimental psychology on a high level and to fur- 

 Tjish a foundation for a science of psychical measurements, 

 «r psychometry. 



What is the reason, then, that we are doing second-rate 

 work when we might do first? The trouble lies, it seems to 

 me, in the lack of a proper training. We attempt to make 

 ■experiments; but how many of us have received a practical 

 training in the use of our apparatus? We make observations ; 

 but how many are familiar with the methods of observation 

 and the computation of errors? We obtain tables of results; 

 but how many know how to formulate the equation express- 

 ing those results? I know that, until 1 was brought face to 

 face with the question of what to do with my figures when I 

 had got them, it had not occurred to me to remedy my de- 

 ficient training by a study of the methods of expressing re- 

 sults. We ail of us daily use light, sound, heat, electricity, 

 etc., in our experiments; but how many are familiar with the 

 units and the methods of measuring these forms of energy? 

 What a psychologist must have is a thorough course of 

 training in psychometry, or the methods of psychical meas- 

 urement. 



Summing up, I would say that what we need in experi- 

 mental psychology is: no quackery, little amateurism, a 

 proper estimation of qualitative work as subordinate, a 

 transformation of the qualitative into quantitative investiga- 

 tions, and, as the means of obtaining all this, a thorough 

 laboratory training. E. W. SCRIPTURE. 



Clark Uoiverslty, Worcester, Ma33. 



THE VESICLES OF SAVI. 



In the Archives Italiennes de Biologie, XVI., 1891, page 

 316, there is a reprint from the Atti delta R. Accad. dei 

 Lincei, VII., 1891, fasc. 6, of Dr. Alessandro Coggi's impor- 

 tant notice of the development of Savi's " appareil follicu- 

 laire nerveux " in the torpedoes. Since Savi's announce- 

 ment of his discovery of these peculiar follicles on the lower 

 surface of the torpedo, 1841-44, an extensive series of publi- 

 cations has been made on the subject. The anatomy has re- 

 ceived attention at the hands of Boll, Leydig, Kolliker, Max 

 Schultze, Mailer, and others; and the nature and functions 

 have been variously determined. Leydig made the vesicles 

 to be one of his three classes of organs for a sixth sense; 

 Wagner supposed tlem to be electrical excitants; but the 

 majority agreed in regarding them as tactile organs. In 

 1888, in my work on the "Lateral Canal System of the 

 Selachia and Holocephala," published by the Museum of 

 Comparative Zoology, it was proved that the vesicles be- 

 longed to the lateral system, as seen on the skates and sharks, 

 and it was shown that they were not confined to the torpedo, 

 but were found on such genera as Urolophus, Potamotrygon, 

 and Disceus of the rays, where they were simple rudimentary 

 remnants of the lateral canals. My conclusions are amply 

 confirmed by Dr. Coggi from the embryology of torpedo, in 

 the early stages of which he traces the ventral canals, as in 

 embryos and adults of other Selachia. He finds various 

 stages of canal disruption corresponding with those I had 

 figured from the Batoids above mentioned. 



Dr. Coggi's assertion that the hypothesis making the vesi- 

 cles of Savi a special modification of the lateral line system 

 was first brought forward by M'Donnell, 1864, is one to which 

 I should take exception. It must be due to misunderstand- 



ing of M'Donnell's statements. That author enumerates five 

 structures that "may be, or have been, confounded with 

 different parts of the lateral line system," and he describes 

 the last one of the five as " The bodies discovered by Savi in 

 the torpedo (appareil folliculaire nerveux) — which last, 

 however, may be related to the lateral line, as I shall after- 

 wards attempt to show." This is suiHciently involved to 

 make his meaning very doubtful. But to prove that M'Don- 

 nell did not advance the idea of identity of follicles and lateral 

 lines we have only to turn to the penultimate paragraph of his 

 article, where he classes the follicles with other tactile organs, 

 and says that they, one and all. appear to be distinct from 

 the system of the lateral line, which, he says, has more the 

 appearance of a cutaneous excretive organ than of one of 

 sensation (Trans. R. Irish Acad., XXIV., 1864, read 1862, 

 page 161). Up to the present I have learned of no proof or 

 assertion of identity of Savi's follicles and the lateral canal 

 system previous to that in my work of 1888. 



Respecting the utility of th^ follicles it may be added here 

 that my conclusions are at variance with those of all who 

 have heretofore discussed the matter, insomuch that I con- 

 sider these organs to be practically without special function, 

 and to represent only a transitory condition of the lateral 

 system, intermediate between functional perfection, in the 

 embryo, and ultimate more or less complete disappearance, 

 during the life of the individual. As the organs are absent 

 from particular species or from older individuals, and are 

 rudimentary and irregular when present, this seems to me 

 the only tenable conclusion. S. Gaeman. 



Museum of Comparative Zoology, 

 Cambridge, Mass., Feb. 29. 



BACTERIA IN DRINKING WATER. 



Dr. W. Migula [Centralbl. f. BaJct. und Parasitenk., 

 Bd. VIII., No. 12, p. 353) makes a contribution to our knowl- 

 edge of this subject which is really a new departure as re- 

 gards the examination of drinking water. He points out 

 that, although considerable stress has been laid on the ex- 

 amination of water for pathogenic organisms, there is no 

 reliable rule to guide the hygienist in his examinations for 

 the ordinary saprophytic organisms and their relation to the 

 purity of water to be used for drinking purposes. Dr. Migula 

 wa.shes out small flasks with bichloride of mercury; then, 

 after rinsing them with the water to be examined, he leaves 

 a specimen in the flask, which is plugged with sterilized 

 cotton wadding and covered with an india-rubber cap. It is 

 not necessary to pack the flasks in ice, as it is assumed that 

 if any of the organisms multiply they will all do so, while 

 if the putrefactive organisms (those that liquefy gelatine) 

 grow more rapidly than the others, independent evidence is 

 obtained of the impurity of the water. Cultivations are 

 made in flat glass dishes in order to save the time required 

 in manipulating plates and tubes during the cooling process. 

 After examining 400 springs, wells, and streams, the author 

 has come to the conclusion that where there are more than 

 ten species in any sample of water, especially when these 

 are not species ordinarily met with, the water should not be 

 used for drinking purposes. He found that in only fifty- 

 nine waters was this the case, but that 169 waters contained 

 more than 1,000 organisms per cubic centimetre, sixty-six of 

 these having over 10,000 (forty over 50,000). From these 

 figures it will be seen that some of the sources of supply 

 would be condemned by the old method but would be passed 

 by the new, and some condemned by the new would be 

 passed by the old. Migula found in all twenty-eight species, 



