Blastogenetic Factors. It has been demonstrated that various chemical substances, such as chloroform, morphia, chloral, etc., have a pronounced influence upon the vital activities of cells. It is well known that microscopic unicellular plants constitute the essential part of yeast. These little cells have the power of causing fermentation in solutions of grape sugar by which alcohol and carbon dioxide are formed, the latter being a gas and escaping as bubbles. If chloroform or ether be added to the solution of sugar, before adding the yeast, no fermentation takes place, for the yeast-cells are paralyzed. But when the yeast is separated from the chloroform solution and rinsed with distilled water, it soon regains the power of causing fermentation in pure solutions of sugar.
Ova and Spermatozoids are subject to the action of drugs in a similar manner. If actively motile spermatozoids of a sea-urchin be placed in a one-half of one per cent. solution of chloral in sea water, it will be found that after five minutes their action will be completely arrested. These motions can soon be restored if the chloral solution be sufficiently diluted with pure sea water. These temporarily paralyzed spermatozoids, when completely recovered, will unite as quickly with ova as fresh spermatozoids. When spermatozoids are kept for half an hour in the chloral solution, a more decided paralysis will be observed, which persists for some time after the removal of the poisonous agent. A few minutes elapse before some of the spermatozoids exhibit feeble movements which finally become active. Even when placed near ova, it is some time before they fertilize them, although several may attach themselves to the egg’s surface. But, finally, fertilization does take place by the penetration of one spermatozoid, and the egg normally develops.
In like manner, if ova are subjected to chloral solution of varying strength, they also are influenced in a marked degree; for, when fertilized, they develop in an abnormal manner. Ordinarily, normal ova are fertilized by one spermatozoid. If fertilized by two or more, they become diseased, and develop pathologically. The chloral solution favors this fertilization by several spermatozoids. The stronger the solution of chloral, the larger the number of spermatozoids that fertilize the ovum. Experiment and observation show that the behavior of the nuclear hereditary mass is modified, during mitosis, by the chloral and other solutions. It is thus seen that the germ-cells of the lower animals can be profoundly modified by various substances.
Equally true is it that the man or woman who makes use of such drugs as alcohol, opium, chloral, and such like, in an intemperate manner, contains these poisons in solution in the blood, circulating to every part of the body, and thus bathing and profoundly influencing the germ-cells. In consequence of this fact an acquired and habitual intemperance will seldom fail to leave its impress upon one or more of the offspring, either like the original vice or one very closely allied to it. Intemperate people not only profoundly impair the health, the intelligence, and the morals of their offspring, by poisoning these delicate germ-cells, but they also transmit the fatal tendency to crave for the very substances that have acted as poisons on these germ-cells before and after fertilization. And one of the saddest features of this great medical truth is that the hereditary units which are concerned in transmitting these grave abnormal tendencies may lie dormant in the germs of one generation, to become active in those of the next; so that children of intemperate parents may lead honorable and temperate lives, and take every pains to rear, in turn, their own children in a wholesome and refining atmosphere, and yet these children of good environment may become intemperate through heredity, so that the sins of the grandparents may be visited, not on the children, but on the grandchildren.
These profound truths should lead all, and especially law-makers, to remember that “the man who inherits from his parents an impulsive or easily tempted nature and an inert will and judgment, and commits a crime under the influence of strong emotion, can no more be placed in the same category of responsibility with a man of more favorable constitution and temperament than can a man who steals a loaf under the pangs of starvation with a merchant who commits a forgery to afford him the means of prolonging a guilty career.”[3]
Not only do certain known poisons circulating in the blood, or other fluid that may bathe the germ-cells of living creatures, profoundly affect the germ-cells, but many other substances probably have great influence upon them. Certainly, the amount and character of the food have a very decided influence on them, as will be understood from the following facts.
According to Yung, who has experimented very extensively upon tadpoles, all tadpoles pass through a bisexual (hermaphroditic) stage, as is the case probably with most animals. During this tadpole phase external influences, and, more particularly, food, determine their fate as regards sex. In Yung’s experiments it was found that when tadpoles were left to themselves, the percentage of females was in the majority, the average being probably about 57 per cent. females and 43 per cent. males. In experimenting with three broods, those fed on beef gave 78 per cent. females; those fed on fish gave 80 per cent. females; and those fed on the highly nutritious flesh of frogs gave 92 per cent. females.
In Mrs. Treat’s interesting experiments on moths and butterflies, it was observed that if caterpillars were confined and starved before they entered the chrysalis state, the resultant moths or butterflies were males, but others of the same brood that had been highly nourished came out females.
The study of bees illustrates the same conclusions. It is well known that in a beehive there are three kinds of inmates, as the queen, the drones, and the workers,—the last-mentioned being females whose reproductive organs are imperfectly developed. It is believed that the eggs that give rise to queens and workers are fertilized and developed normally. But it is a very curious fact that the eggs which develop into drones do so without fertilization (parthenogenesis). What factor or factors decide the destiny of the two former, determining whether a given ovum will develop into a queen, and thus be the possible mother of a new generation, or stay at the lower grade of a working, non-fertile female? These factors are the quality and quantity of the food. An abundance of what is called royal food causes the development of the larva in such a way that the queen with her reproductive organs is formed. If a larva on the road to develop into a worker (non-fertile female) “receive by chance some crumbs from the royal superfluity,” it is found that the reproductive organs may develop to such an extent that workers partially fertile may be formed. A worker larva may, by this royal food, be intentionally reared into a queen bee.