▼OL. XII.] PHILOSOPHICAL TRANSACTIONS. 451 



Fig. 4, represents the glandulae renales. A the glandula renalis of the right 

 side ; B that of the left side; C the vena cava; D a vein or ductus opening from 

 the cavity of this gland and entering the vena cava; Ea vein from the left glan- 

 dula renalis, and is inserted into a branch of the left emulgent. 



Ohservationes D. Anthonh Leuwenhoeck, de Natis ^ semine genitali Animalculis.*- 

 Nee non Auctoris harum Transactionum Responsa. N° 142, p. J 040. f 



Obser\'atoris Epistola Honoratiss. D. D. Vice-comiti Brouncker, Latin^ con- 



scripta; Dat. Nov. 1677, quam ipsissimis hue transmissis verbis inserendam 



Auctor censuit. 



Postquam Exc. Dominus Professor Cranen, me visitatione sua saepius hono- 

 rarat, literis rogavit. Domino Ham cognato suo, quasdam observationum mearum 

 videndas darem. Hie Dominus Ham me secundo invisens, secum in lagunculil 

 vitrei semen viri, Gonorrhaed laborantis, spont^ destillatum, attulit, dicens, se 

 post paucissimas temporis minutias (cum materia ilia jam in tantum esset resoluta, 

 ut fistulas vitreae immitti posset) animalcula viva in eo observasse, quae caudata, 

 et ultra 24 horas non viventia judicabat: Idem referebat se animalcula observasse 

 mortua post sumtam ab aegroto terebinthinam. Materiam praedictam fistulas 

 vitreae immissam, praesente Domino Ham, observavi, quasdamque in ea creaturas 

 viventes; at post decursum 2 aut 3 horarum, eandem solus materiam observans, 

 mortuas vidi. 



Eandem materiam (semen virile) non aegroti alicujus, non diuturna conser- 

 vatione corruptam, vel post aliquot momenta fluidiorem factam, sed sani viri 

 statim post ejectionem, ne interlabentibus quidem sex arteriae pulsibus, saepius- 

 cule observavi, tantamque in ea viventium animalculorum multitudinem vidi, ut 

 interdum plura quam 1000, in magnitudine arenae sese moverent. Non in toto 

 semine, sed in materia fluida crassiori adhaerente, ingentem illam animalculorum 

 multitudinem observavi ; in crassiori vero seminis materia, quasi sine motu jace- 

 bant; quod inde provenire mihi imaginabar, quod materia ilia crassa ex tarn variis 

 cohaereat partibus ut animalcula in ea se movere nequirent. Minora globulis 

 sanguini ruborem adferentibus haec animalcula erant: ut judicem millena millia 

 arenam grandiorem magnitudine non aequatura, Corpora eorum rotunda, ante- 



* Tlie discovery of the spermatic animalcules has always been considered as one of the most ex- 

 traordinary, which the microscope is capable of exhibiting. They are observable in the seminal 

 fluid of almost all animal sj and though the Leuwenhoeckian theory of generation be now exploded, 

 yet the existence of such legions of animated beings affords a wide field for philosophical speculation. 

 The subject however being now sufficiently familiar to the naturalist, it seems unnecessary to preserve 

 more of Mr. Leuwenhoeck's paper than what is here printedj and which it seems more proper to 

 give in the original Latin translation from the Dutch, than in English. 



3 M 2 



